Antenna system for communicating with mobile devices

ABSTRACT

Systems and methods for providing network access to mobile devices that travel with a vehicle, such as a train, a bus, a boat, etc. along or adjacent to a relatively fixed path that may extend over a large geographic area. Mobile devices access the network through stationary access points arranged along or adjacent to the path and communicate with a communication network. The communication network may be arranged as an asynchronous transfer mode (ATM) local area network emulation (LANE) network. One of the mobile devices may be a mobile access point which can couple other mobile devices to the network and record authentication information of other mobile devices so that fast transitions can be made from one stationary access point to another as the vehicle moves along the path.

CROSS REFERENCE TO RELATED APPLICATIONS

The instant application claims priority under 35 USC 119(e) to U.S.provisional patent application No. 60/838,752 filed Aug. 18, 2006 andentitled SYSTEM AND METHOD OF WIRELESSLY COMMUNICATING WITH MOBILEDEVICES, which is hereby incorporated herein by reference. The instantapplication is related to co-pending applications SYSTEM AND METHOD OFAUTHENTICATING MOBILE DEVICES, SYSTEM FOR PROVIDING REDUNDANTCOMMUNICATION WITH MOBILE DEVICES, and SYSTEM AND METHOD OF WIRELESSLYCOMMUNICATING WITH MOBILE DEVICES, each by Cooper G. Lee, filedconcurrently herewith.

BACKGROUND

1. Field of Invention

The present invention relates to wireless communication and moreparticularly to wireless communication with a plurality of mobiledevices.

2. Discussion of Related Art

Wireless networks provide mobility and convenience to users of variousmobile devices. Such networks have become pervasive and may now be foundin homes, workplaces, and even public and commercial spaces such asparks and coffee shops. Wireless network access is generally limited inrange to an area relatively near a wireless access point. In public orcommercial spaces, the area in which a wireless network is accessible isoften referred to as a wireless hotspot. One popular wireless networkingtechnology is referred to as Wi-Fi and is defined by the various IEEE802.11 specifications.

A typical wireless network user may connect to a different wirelessnetwork in his or her home, at a local restaurant or coffee shop, and athis or her workplace. The user may also connect to a single wirelessnetwork through different access points as the user moves from onelocation to another, for example, as the user moves from one floor of anoffice building serviced by one wireless router to another floor of thesame office building serviced by a different wireless router. Eachconnection to a new wireless network or a new access point generallyrequires establishing a new connection to the network. This may includeauthenticating the user and mobile device to a network authenticationserver before the user is allowed to fully access the network. Whenusers are moving relatively quickly, such as when they are travelingalong with a vehicle, such reauthentication may cause gaps in networkconnectivity.

Moreover, wireless networking may be limited by the active range of awireless access point. So users may experience limited mobility based onthe positioning and strength of a wireless access point through whichthey couple to a communication network. This range may be altered byenvironmental features, such as tunnels, walls, buildings, geography,etc, further limiting the range of wireless networks.

SUMMARY OF INVENTION

In accordance with one aspect of the present invention, it is recognizedthat establishing a new connection to a wireless network as a user movesamong networks or access points may cause a break in network accessleaving the user temporarily without network access. To help preventsuch breaks in network access, a communication network may be configuredto minimize the time needed to establish a new connection to thenetwork. This may be accomplished, for example, by reducing the timeneeded to authenticate a user or mobile device with a networkauthentication server, or, for another example, by arranging accesspoints into authentication groups having a shared authentication cachethat may provide some authentication without communicating with theauthentication server.

To further prevent such network access breaks, access points of acommunication network may be disposed so that the range of each accesspoint overlaps with the range of a neighboring access point. The overlapmay be great enough so the mobile device may complete establishing aconnection through the neighboring access point before leaving the rangeof the access point through which the mobile device currently accessesthe network. Such an arrangement may allow a user to travel amongneighboring access points without experiencing a break in networkaccess.

In accordance with one aspect of the present invention, it is realizedthat mobile device users traveling on or in a vehicle along a path maydesire wireless network access without access interruptions. Forexample, a plurality of users traveling on or in a vehicle, such as atrain, boat, car, etc., moving from one location to another, such asfrom one train station to another, may want to access such a wirelessnetwork to check email, surf the web, access a work related virtualprivate network (VPN), etc. To facilitate such network access, aplurality of stationary access points may be arranged along or adjacentto the path traveled by the vehicle. The path and network may, thereby,span a large geographic area, such as from one city to another or fromone state to another.

The plurality of stationary access points may be connected to each otherand the network by wired or wireless communication methods. Eachstationary access point of the plurality of stationary access points maybe configured to forward data among the mobile devices and the network.Each stationary access point may be arranged to maintain a line of sightand a wireless communication channel with the mobile devices while theyare in a communication range of the stationary access point to improveaccess quality as the mobile devices move along the path.

In accordance with one aspect of the present invention, it is recognizedthat establishing a new connection for a plurality of mobile devices atnearly the same time, such as when a vehicle carrying the plurality ofmobile devices moves from one stationary access point to a newstationary access point, may delay the establishment of some of the newconnections, for example because a bandwidth limit may be reached or anauthentication server may be overwhelmed with authentication requestsfor each device of the plurality of mobile devices. To prevent suchdelay, the mobile device may include a mobile access point that iscoupled to the vehicle and travels along with one or more other mobiledevices, such as a mobile host device (e.g., a laptop, a PDA, a cellulartelephone, etc.) or a mobile forwarding device (e.g., a router, abridge, a switch, a repeater, etc.). The mobile access point may connectto the stationary access points disposed along the path. The othermobile devices may connect to the mobile access point in order to accessthe network associated with the stationary access points.

The mobile access point may record connection information, such asauthentication information, for each mobile host device of the pluralityof mobile host devices so that the mobile host devices can move amongthe access points without needing to reauthenticate or establish a newconnection to a stationary access point. Rather, in such aconfiguration, the mobile access point may be the only device that mayneed to authenticate and establish such a new connection when the mobilehost devices and mobile access point move among stationary accesspoints, thereby limiting the amount of authentication and other newconnection related traffic.

In accordance with another aspect of the present invention, it isrecognized that certain types of network connection (e.g., secure socketlayer (SSL), VPN, etc.) may depend upon a static network layer address(e.g., IP address) that may not be maintained as a user moves amongaccess points of a conventional wireless network, especially a wirelessnetwork that spans a large geographic area. To maintain such networklayer addresses as a mobile host device moves from one stationary accesspoint to another of a communication network, devices of thecommunication network may be configured to transparently forwardinformation through the communication network based on data link layeraddress information. For example, the communication network may beconfigured as an asynchronous transfer mode (ATM) local area networkemulation (LANE) having virtual circuits connecting the mobile devicesthrough the network. Such a configuration may allow mobile devices tomaintain one network layer address as the devices travel among multiplestationary access points by updating the virtual circuits as the devicesmove.

Wireless communication used in various embodiments of the presentinvention may include any type of wireless communication between two ormore devices without any direct mechanical attachment, such as radiofrequency or optical communication. An example wireless communicationthat may be used includes any of the well-known IEEE 802.11 protocols.

Another aspect of the present invention includes a communication system.In some embodiments, the communication system comprises a plurality ofstationary access points coupled to a communication network, and amobile access point configured to communicate with the plurality ofstationary access points and provide a plurality of host devices accessto the communication network without address renegotiation, wherein themobile access point and the plurality of host devices move relative tothe plurality of stationary access points.

In one embodiment, the mobile access point communicates with at leastone of the plurality of host devices using a wireless network. Inanother embodiment, the mobile access point communicates with theplurality of stationary access points using a wireless network. In someimplementations, the wireless network may include a wireless networkusing an IEEE 802.11 protocol.

In some embodiments, the mobile access point is configured to providethe plurality of host devices access to the communication networkthrough the wireless network to one stationary access point of theplurality of stationary access points at a time. In someimplementations, the one stationary access point is a stationary accesspoint of the plurality of stationary access points that provides astronger wireless communication signal to the mobile access point thanat least one other stationary access point of the plurality ofstationary access points. In other embodiments, to provide access to thecommunication network to at least one of the plurality of host devices,the mobile access point communicates through a wireless network with amobile forwarding device.

In some embodiments, the communication network is connected to anexternal communication network by a forwarding device. In someimplementations, the forwarding device includes an edge router. Infurther implementations, data addressed to a network layer address of afirst host device of the plurality of host devices and received by theforwarding device from the external communication network is forwardedfrom the forwarding device to the first host device through the mobileaccess point and at least one of the plurality of stationary accesspoints based on a data link layer address of the first host device.

In other embodiments, the plurality of host devices includes at leastone of a laptop computer, a personal digital assistant (PDA), and acellular telephone. In still other embodiments, at least one of theplurality of stationary access points couples to the communicationnetwork through a wired connection. In further embodiments, a firststationary access point of the plurality of stationary access pointscouples to the communication network through a second stationary accesspoint of the plurality of stationary access points. In someimplementations, the first stationary access point couples to thecommunication network using a wired network to the second stationaryaccess point. In other implementations, the first stationary accesspoint couples to the communication network using a wireless network tothe second stationary access point.

In some embodiments, the mobile access point is coupled to a vehicle. Insome implementations, the vehicle includes at least one of a boat, atrain, a bus, and a car. In one implementation, the vehicle moves alonga path, and the plurality of stationary access points are arrangedadjacent to the path.

Another aspect includes a method of forwarding data to a moving hostdevice. In some embodiments, the method comprises acts of maintaining,in a first forwarding device of a plurality of forwarding devices of acommunication network, forwarding information for the moving host devicebased on a data link layer address of the moving host device, receivingdata addressed to a network layer address of the moving host device atthe first forwarding device, and forwarding a representation of at leasta portion of the received data along a path to the data link layeraddress of the moving host device based on the maintained forwardinginformation.

Some embodiments further comprise an act of addressing, at the firstforwarding device, the representation of at least the portion of thereceived data to the data link layer address of the moving host device.In other embodiments, the act of maintaining comprises an act ofestablishing a new virtual circuit through at least a portion of a newpath from the first forwarding device to the moving host device when thepath to the moving host device from the first forwarding device changes.In some implementations, the first forwarding device includes a mobileaccess point.

In some embodiments, the first forwarding device includes at least onestationary access point. In some implementations, the at least onestationary access point includes a first stationary access point whenthe moving host device is in a first position and a second stationaryaccess point when the moving host device is in a second position. Oneimplementation further comprises establishing a first wirelessconnection between the first stationary access point and a mobile accesspoint when the moving host device is in the first position andestablishing a second wireless connection between the second stationaryaccess point and the mobile access point when the moving host device isin the second position.

In other embodiments, the moving host device includes at least one of alaptop computer, a personal digital assistant (PDA), and a cellulartelephone. In still other embodiments, the act of maintaining includesacts of sending, responsive to the path to the moving host device fromthe first forwarding device changing, updated forwarding information tothe first forwarding device through the communication network along atleast a portion of the changed path; and associating, at any forwardingdevices along the portion of the changed path and the first forwardingdevice, the updated forwarding information with the moving host device.In some implementations, the act of associating includes an act ofestablishing a new virtual circuit from the mobile host device to thefirst forwarding device. In some embodiments, the act of forwardingcomprises an act of forwarding a plurality of asynchronous transfer mode(ATM) cells, wherein each of the cells includes at least a portion ofthe representation of the portion of the received data. In otherembodiments, the act of forwarding comprises an act of forwarding therepresentation using ATM local area network emulation (LANE) to themoving host device.

A further aspect includes a communication system comprising a firstantenna system comprising a plurality of first antennas mounted to afirst supporting structure, each of the plurality of first antennashaving a main lobe oriented in a different direction; and a secondantenna system comprising a plurality of second antennas mounted to asecond supporting structure, each of the plurality of second antennashaving a main lobe oriented in a different direction, the main lobe ofat least one of the plurality of second antennas being oriented in adirection opposing the main lobe of at least one of the plurality offirst antennas, wherein the first antenna system and the second antennasystem are disposed at spaced apart positions along or adjacent to apath traversed by a vehicle, such that the vehicle does notsubstantially obstruct the main lobes of the plurality of first antennasor the plurality of second antennas as the vehicle traverses the path.

In some embodiments, at least 40% of an energy radiated from a firstantenna of the plurality of first antennas and from a second antenna ofthe plurality of second antennas is not obstructed by the vehicle as thevehicle traverses the path. In other embodiments, the first antennasystem includes at least one of a battery and a solar power supplyconfigured to power the plurality of first antennas.

Still other embodiments further comprise a mobile antenna coupled to thevehicle, wherein the first antenna system is configured to communicatewith the mobile antenna through at least one of the plurality firstantennas when the mobile antenna is within a communication range of thefirst antenna system, and the second antenna system is configured tocommunicate with the mobile antenna through at least one of theplurality of second antennas when the mobile antenna is within acommunication range of the second antenna system. In someimplementations, the communication range of the first antenna systemoverlaps the communication range of the second antenna system. In otherimplementations, each of the first and second antenna systems is coupledto a communication network. In some implementations, the first antennasystem is coupled to the communication network through a wiredconnection. In some implementations, the second antenna system iscoupled to the communication network through the first antenna system.In one implementation, the second antenna system is coupled to thecommunication network through the first antenna system by a wiredconnection to the first antenna system. In other implementations, thesecond antenna system is coupled to the communication network throughthe first antenna system by a wireless network with the first antennasystem. In one implementation, the first antenna system includes atleast one third antenna communicating over the wireless network to atleast one fourth antenna of the second antenna system to couple thesecond antenna system to the communication network through the firstantenna system. In another implementation, the wireless network includesa wireless network using an IEEE 802.11 protocol.

In other embodiments, the mobile antenna is coupled to a mobile accesspoint configured to provide a plurality of host devices access to thecommunication network through communication with the first and secondantenna systems. In still other embodiments, the plurality of hostdevices includes at least one of a laptop computer, a personal digitalassistant (PDA), and a cellular telephone. In yet further embodiments,the mobile access point is configured to provide access to thecommunication network through the first antenna system when a firstsignal strength of the first antenna system is stronger than a secondsignal strength of the second antenna system. In some implementations,the mobile access point is configured to provide access to thecommunication network through the second antenna system when the secondsignal strength is stronger than the first signal strength. In otherimplementations, the mobile access point is configured to authenticatewith the second antenna system before the second signal strength isstronger than the first signal strength. In some other implementations,the mobile access point communicates with the first and second antennasystems through a wireless network. In one implementation, the wirelessnetwork includes a wireless network using an IEEE 802.11 protocol.

In further embodiments, the mobile access point communicates with theplurality of host devices through at least one wireless network. In oneimplementations, the wireless network includes a wireless network usingan IEEE 802.11 protocol.

Yet a further aspect includes an antenna system for communicating with amobile device, comprising a support; a plurality of first antennasmounted to the support, each first antenna of the plurality of firstantennas being configured to communicate with the mobile device when themobile device is more than a minimum communication distance from thesupport and less than a maximum communication distance from the support;and at least one second antenna mounted to the support and configured tocommunicate with the mobile device when the mobile device is less thanthe minimum communication distance from the support.

In some embodiments, the communication system further comprises at leastone connection device coupled to the support and configured tocommunicate with a communication network. In some implementations, themobile device includes a mobile access point and the communicationsystem is configured to provide access to the communication network to aplurality of host devices coupled to the mobile access point bycommunicating with the mobile access point through at least one of theplurality of first antennas and the at least one second antenna.

In other embodiments, the at least one connection device comprises aplurality of third antennas mounted to the support. In someimplementations, at least one antenna of the plurality of third antennasis configured to communicate with at least one second communicationsystem. In some implementations, the at least one antenna of theplurality of third antennas is configured to communicate with thecommunication network through a wireless network with the at least onesecond communication system. In one implementation, the wireless networkincludes a wireless network using an IEEE 802.11 communication protocol.

In other embodiments, the at least one connection device comprises awired connection to the communication network. In one implementation,the wired connection includes at least one of a wire and an opticalfiber. In other implementations, the wired connection connects thecommunication system to a forwarding device coupled to the communicationnetwork. In still other implementations, the wired connection to thecommunication network includes at least one wired connection to at leastone second communication system. In another embodiment, the plurality offirst antennas are parabolic dish antennas and the at least one secondantenna is an omnidirectional antenna.

A still further aspect of the present invention includes a mobilecommunication system comprising a first communication system configuredto communicate with at least one host device; and a second communicationsystem configured to communicate with a plurality of stationary accesspoints and the first communication system, wherein the mobilecommunication system is configured to authenticate the secondcommunication system with a first stationary access point of theplurality of stationary access points by authenticating the secondcommunication system with an authentication server, and wherein themobile communication system is further configured to authenticate thesecond communication system with a second stationary access point of theplurality of stationary access points without reauthenticating thesecond communication system with the authentication server.

In some embodiments, the mobile communication system is configured toauthenticate the second communication system with the second stationaryaccess point by accessing an authentication cache indicative of whetherthe second communication system has previously been authenticated by theauthentication server. In other embodiments, the second communicationsystem and the plurality of stationary access points communicatewirelessly.

In still other embodiments, the first communication system is configuredto provide, to the at least one host device, access to a communicationnetwork coupled to the plurality of stationary access points. In someimplementations, the first communication system is configured tocommunicate with the at least one host device using a wirelesscommunication network. In other implementations, the first communicationsystem is configured to communicate with the at least one host devicethrough at least one mobile forwarding device.

In yet further embodiments, the second communication system isconfigured to communicate with the plurality of stationary access pointswithout address renegotiation of the second communication system. Ineven further embodiments, the second communication system is configuredto couple to a communication network through a different respective oneof the plurality of stationary access points as the mobile communicationsystem moves. In one implementation, the second communication system isconfigured to select a current one of the plurality of stationary accesspoints through which to couple to the communication network based, atleast in part, on a signal strength of a communication signal betweenthe second communication system and the plurality of stationary accesspoints.

In a further embodiment, the mobile communication system is coupled to avehicle. In one implementation, the vehicle includes at least one of aboat, a train, a bus, and a car, and the at least one host deviceincludes at least one of a laptop computer, a personal digitalassistant, and a cellular telephone.

Another aspect includes a method of authenticating a mobile device. Inone embodiment, the method comprises receiving an authentication requestfrom the mobile device at a first stationary access point;authenticating the mobile device to the first stationary access point byrequesting authentication from an authentication server; storingauthentication information identifying the mobile device in anauthentication cache associated with the first stationary access pointand at least one second stationary access point; receiving anauthentication request from the mobile device at the at least one secondstationary access point; and authenticating the mobile device to thesecond stationary access point by referencing the stored authenticationinformation.

In some embodiments, authenticating the mobile device to the at leastone second stationary access point takes less than about 2 milliseconds.Some embodiments further comprise grouping the first stationary accesspoint and the at least one second stationary access point so that thestored information identifying the mobile device can be provided to eachat least one second stationary access point in the group by referencingthe stored authentication information and without requesting furtherauthentication from the authentication server. In one implementation,grouping includes maintaining the authentication cache in a WLCCPcontroller and permitting authentication access to the WLCCP controllerby each of the first stationary access point and each of the at leastone second stationary access point.

Some embodiments of this aspect further comprise providing access to acommunication network coupled to the first stationary access point andthe at least one second stationary access point to the mobile device. Insome implementations, providing access to the communication networkincludes maintaining forwarding information for the mobile device basedon a data link layer address of the mobile device. One implementationfurther comprises forwarding information addressed to a network layeraddress of the mobile device to the mobile device based on themaintained forwarding information. In other implementations, providingaccess includes providing access without address renegotiation by themobile device.

In some embodiments, requesting authentication from the authenticationserver includes requesting authentication from a RADIUS server. In otherembodiments, the mobile device traverses a path proximate the firststationary access point and the at least one second stationary accesspoint at an average rate of travel, and the act of storing theauthentication information includes storing the authenticationinformation for a period of time sufficient to allow the mobile deviceto traverse the path at the average rate of travel. In someimplementations, authenticating the mobile device with theauthentication server takes less than about 100 milliseconds.

Other embodiments further comprise providing access to a communicationnetwork coupled to the first stationary access point and the at leastone second stationary access point to a plurality of host devicescoupled to the mobile device. In some implementations, providing accessto the communication network includes maintaining forwarding informationcorresponding to each respective host device of the plurality of hostdevices based on data link layer addresses of the respective hostdevice. One implementation further comprises forwarding informationaddressed to a network layer address of a first host device of theplurality of host devices to the first host device based upon themaintained forwarding information corresponding to the first hostdevice. In other implementations, providing access includes providingaccess without address renegotiation by the mobile device.

An even further aspect of the present invention includes a communicationsystem for communicating with a mobile device. The communication systemcomprises a plurality of antenna systems, each respective antenna systemof the plurality of antenna systems being configured to communicate withthe mobile device when the mobile device is within a communication rangeof the respective antenna system, wherein the plurality of antennasystems are disposed at spaced apart positions along a path traversed bythe moving vehicle so that the mobile device is within a communicationrange of at least one antenna system of the plurality of antenna systemsas it traverses the path and a line of sight is maintained between themobile device and the at least one antenna system of the plurality ofantenna systems.

In some embodiments, the mobile device is a mobile access pointconfigured to provide network access to a plurality of host devices bycommunicating with the at least one antenna system of the plurality ofantenna systems. In other embodiments, the plurality of host devicesincludes at least one of a laptop computer, a personal digital assistant(PDA), and a cellular telephone. In still other embodiments, the mobileaccess point is configured to provide network access to the plurality ofhost devices by communicating with the at least one antenna system ofthe plurality of antenna systems through a wireless communicationnetwork. In some implementations, the wireless communication networkincludes a wireless network using an IEEE 802.11 communication protocol.

In further embodiments, a subset of the plurality of antenna systems isconfigured as an antenna group that includes an antenna group controllerto facilitate low latency movement of the mobile device fromcommunication with a first antenna system of the subset of antennasystems to communication with a second antenna system of the subset ofantenna systems. In some implementations, the subset of antenna systemsis arranged along an external portion of a curve in the path. In otherimplementations, the antenna group controller facilitates movement ofthe mobile device from communication with the first antenna system ofthe subset of antenna systems to communication with the second antennasystem of the subset of antenna systems by authenticating the mobiledevice to the second antenna system. In one implementation, the antennagroup controller includes at least one WLCCP controller. In anotherimplementation, the antenna group controller includes an authenticationcache, and authenticating the mobile device to the second antenna systemincludes querying the authentication cache.

In still further embodiments, the plurality of antenna systems aredisposed at spaced apart positions along the path traversed by themoving vehicle so that the mobile device is within the communicationrange of at least two antenna systems of the plurality of antennasystems as it traverses the path and a line of sight is maintainedbetween the mobile device and the at least two antenna systems of theplurality of antenna systems.

Another aspect of the present invention includes a communication systemfor communicating with at least one mobile device, comprising: aplurality of antenna systems, each respective antenna system of theplurality of antenna systems being configured to communicate with themobile device when the mobile device is within a communication range ofthe respective antenna system, wherein the plurality of antenna systemsare disposed at spaced apart positions along a path traversed by themobile device and positioned relative to one another so that when afirst antenna system of the plurality of antenna systems that is closestto the mobile device cannot communicate with the mobile device, themobile device can communicate with at least one working second antennasystem of the plurality of antenna systems that is disposed adjacent tothe first antenna system.

In some embodiments, the communication range of the first antenna systemoverlaps with the communication range of the at least one working secondantenna system. In other embodiments, the at least one working secondantenna system includes a plurality of working second antenna systems.In some implementations, the communication range of each of theplurality of working second antenna systems includes a communicationrange overlap in which the communication range of a first of theplurality of working second antenna systems overlaps the communicationrange of a second of the plurality of working second antenna systems. Inthis implementation, the communication overlap includes an area in whichthe mobile device may complete a connection process to each of theplurality of working second antenna systems. In one implementation, theconnection process includes an authentication process.

Another aspect includes a mobile access point configured to provideaccess to a communication network to a plurality of host devices,wherein the communication system is configured to determine a geographiclocation of the plurality of host devices based, at least partially, ona determination of a geographic location of the mobile access point.

In some embodiments, the determination of the geographic location of themobile access point is based on the location of a global positioningdevice coupled to the mobile access point. In some implementations, themobile access point is configured to provide access to the communicationnetwork by communicating with at least a subset of a plurality ofstationary access points coupled to the communication network. In otherimplementations, the subset of the plurality of stationary networkaccess points changes as the mobile access point moves relative to theplurality of stationary access points.

In other embodiments, the determination of the geographic location ofthe mobile access point is based, at least partially, on the knowngeographic location of the subset of the plurality of stationary accesspoints communicating with the mobile access point. In someimplementations, the determination of the geographic location of themobile access point is based, at least partially, on at least onecharacteristic of at least one wireless communication signal between thesubset of the plurality of stationary access points and the mobileaccess point. In one implementation, the at least one characteristic ofthe at least one wireless communication signal is a signal strength. Inanother implementation, the signal strength includes a signal strengthof at least one wireless network used by the mobile access point tocommunicate with the plurality of stationary access points.

In some embodiments, information is delivered to the plurality of hostdevices based on the determined geographic location of the plurality ofhost devices. In some implementations, the plurality of host devicesincludes at least one of a laptop computer, a personal digital assistant(PDA), or a cellular telephone.

Further features and advantages of the present invention as well as thestructure and operation of various embodiments of the present inventionare described in detail below with reference to the accompanyingdrawings. In the drawings, like reference numerals indicate functionallysimilar elements. Additionally, the left-most one or two digits of areference numeral identifies the drawing in which the reference numeralfirst appears.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In thedrawings, each identical or nearly identical component that isillustrated in various figures is represented by a like numeral. Forpurposes of clarity, not every component may be labeled in everydrawing. In the drawings:

FIG. 1A illustrates an example communication network coupled to aplurality of stationary access points consistent with principles of thepresent invention;

FIG. 1B illustrates a geographically wide network communicating as alocal area network consistent with principles of the present invention;

FIG. 2 illustrates a view of a first exemplary stationary access pointconsistent with principles of the present invention;

FIG. 3 illustrates a view of a second exemplary stationary access pointconsistent with principles of the present invention;

FIG. 4 illustrates a view of a third exemplary stationary access pointconsistent with principles of the present invention;

FIG. 5 illustrates a vehicle traveling near a plurality of stationaryaccess points consistent with principles of the present invention;

FIGS. 6A, and 6B illustrate example leaky coaxial cable hangers that maybe used in some embodiments;

FIG. 7 illustrates a train traveling near a plurality of stationaryaccess points consistent with principles of the present invention;

FIG. 8 illustrates a flow chart of an example process performed by astationary access point consistent with principles of the presentinvention; and

FIG. 9 illustrates a flow chart of an example process performed by amobile access point consistent with principles of the present invention.

DETAILED DESCRIPTION

Various aspects of the invention are not limited in their application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the drawings. Aspects ofthe invention are capable of other embodiments and of being practiced orof being carried out in various ways. Also, the phraseology andterminology used herein is for the purpose of description and should notbe regarded as limiting. The use of “including,” “comprising,” or“having,” “containing,” “involving,” and variations thereof herein, ismeant to encompass the items listed thereafter and equivalents thereofas well as additional items.

The present invention relates generally to providing network access tomobile devices. Some aspects of the invention relate to mobile devicestraveling with a vehicle, such as a train, a bus, a boat, etc., along oradjacent to a relatively fixed path. Network access may be provided tothe mobile devices through a plurality of stationary access points thatare arranged along or adjacent to the path.

In one aspect of the present invention, one of the mobile devices mayinclude a mobile access point. The mobile access point may be used tocouple one or more other mobile devices to the network. In anotheraspect of the present invention, the mobile access point may recordauthentication information of the one or more other mobile devices sothat a relatively fast transition can be achieved among stationaryaccess points as the vehicle and thereby the mobile devices move alongthe path, as described in more detail below.

In effect, the combination of various aspects of the present inventionmay result in one moving network, which comprises the mobile accesspoint and one or more other mobile devices such as mobile host devicesand/or mobile forwarding devices, and one stationary network, whichcomprises the stationary access points and other elements, such asservers, forwarding devices, etc. The moving network may move relativeto the stationary network and may couple to the stationary network togain access to resources of the stationary network. Such coupling mayresult in the mobile devices coupled to the moving network having accessto the stationary network without experiencing serious, if any, delaysor renegotiating network addresses.

In accordance with one aspect of the present invention, one or moreservers 103 may be coupled to a communication network 101, asillustrated in FIG. 1A. The plurality of servers 103 may provide one ormore network services to devices coupled to communication network 101.The plurality of servers 103 may include an authentication server 105, aregistration server 107, a dynamic host configuration protocol (DHCP)server 109, a structured query language (SQL) server 111, a networkmaintenance and/or monitoring server 113, a content server 115, and anyother server configured to provide functionality to communicationnetwork 101 and/or devices coupled to communication network 101.

Any of the servers may be configured as a single device, such as asingle general purpose computer, or a cluster of devices, such asplurality of blades. In some embodiments of the present invention,authentication server 105 may include a well-known remote authenticationdial in user service (RADIUS) authentication server. According to oneaspect of the present invention, it is appreciated that as any mobiledevice moves among networks or network access points, an authenticationprocess may be performed by the new network or network access point.However, such an authentication may conventionally involve anunacceptable delay that may result in a loss of network access while thedevice awaits authentication.

To improve speed of authentication, which may cause interruptions innetwork access, in some embodiments of the present invention,authentication server 105 may limit responses to an authenticationrequest to either a positive acknowledgement or a negative rejection ofthe authentication request. To further improve the speed ofauthentication, authentication server 105 may be configured to perform alimited specialized set of operations, for example, receive anauthentication request from communication network 101, convert the dataof the received request directly into a SQL query, execute the SQL querylocally or through a networked SQL server 111, convert the result of theSQL query into an authentication response, and transmit the responsethrough communication network 101. In accordance with one embodiment,authentication server 105 may be configured to respond to authenticationrequests at a speed sufficient to prevent an interruption of service asa mobile device moves between one stationary access point and another,as described in more detail below. The needed speed of authenticationmay vary based on the movement speed of the mobile device and anyoverlap in the communication regions of the relevant stationary accesspoints, as is discussed below. In one implementation, authenticationserver 101 may be configured to respond to an authentication request inless than approximately 100 milliseconds.

A plurality of forwarding devices 117, 119 may also be coupled tocommunication network 101. The plurality of forwarding devices 117, 119may include routers, switches, bridges, gateways, repeaters, accesspoints, and any other device configured to receive data and forward datatowards a destination of the data. Each forwarding device may beconfigured to direct data from a source towards a destination throughcommunication network 101. Data directed from one location to anotherlocation through communication network 101 may pass through many suchforwarding devices.

Each forwarding device may determine how to forward information to itsintended destination. This determination may cause an unwanted delay inthe transmission of the information to the destination. In someimplementations of the present invention, forwarding devices 117, 119may be configured to forward data using a well-known forwardingtechnique based on a network layer (e.g., layer 3 of the open systemsinterconnection (OSI) model) whereby the direction of data may bedetermined by the network layer address (e.g., internet protocol (IP)address) of the destination. In other implementations of the presentinvention, forwarding devices 117, 119 may be configured to forward databased on the data link layer (e.g., layer 2 of the OSI model) wherebythe direction of data may be determined by the data link layer address(e.g., media access control (MAC) address) of the destination. Use ofdata link layer forwarding techniques may improve forwarding speedcompared with network layer forwarding techniques because data linklayer forwarding techniques may not include a step of examining networklayer destination information. Further, it is appreciated that if ageographically dispersed network is created in the same network layer,client addressing using network layer information does not change asclients change location within the network. Such stable networkaddressing reduces lost packets and the need to renegotiate addresses asa client moves.

Forwarding information based on data link layer information is oftenreferred to as MAC-layer bridging or switching. Forwarding informationbased on network layer information is often referred to as routing. Anyreference to forwarding or forwarding techniques includes directing datain any fashion, including, but not limited to, by data link and/ornetwork layer information.

One data link layer forwarding technique that may be used by forwardingdevices 117, 119 to forward data through communication network 101 isasynchronous transfer mode (ATM) switching. Use of ATM switching mayprovide a high speed method of forwarding information from one locationof communication network 101 to another location. Forwarding devices117, 119 configured to use ATM switching may establish virtual circuitsamong each other through which information may be directed. The virtualcircuits may map a path through which data may travel, at least aportion of the way, from a source to a destination. A virtual circuitmay be established for each destination coupled to communication network101.

A plurality of end nodes, including the plurality of servers 103 andother devices, may be coupled to communication network 101 throughforwarding devices 117, 119. One or more of the end nodes may beconfigured to communicate with the forwarding devices through a directconnection using the ATM data link protocol or some other data linkprotocol such as Ethernet. In some embodiments, a forwarding device maybe configured to communicate with end nodes using non-ATM data linkprotocols and convert that communication to an ATM data link protocolfor transmission through communication network 101.

In some embodiments, forwarding devices 117, 119 may be configured tosupport a well-known ATM local area network emulation (LANE) allowingdevices to couple to communication network 101 as if they were part of asingle local area network (e.g., a network connected on the same datalink) even if they are geographically distant and actually connected todifferent local networks. ATM LANE may allow high speed forwardingtechniques based on data link layer addresses to quickly direct datafrom one location of communication network 101 to another location ofthe communication network even where the locations are geographicallydistant from each other or separated from each other by an externalcommunication network (e.g., the Internet). ATM LANE may also allow aforwarding of information over long distances by data link layertechniques, quality of service selections that improve performance ofhigh priority or streaming traffic, traffic and network management basedvirtual circuits, and high bandwidth capabilities.

FIG. 1B illustrates a communication network 151 spanning a largegeographical area through a different communication network 153.Communication network 151 includes two physically separate networksections 155, 157 separated by a different communication network 153.Each network section 155,157 includes a plurality of host devices 159,161 connected to a forwarding device 163, 165 through a data link 167,169. The data links may be arranged to use any data link communicationprotocol that may be the same or different from each other or theprotocol used to communicate through the different communication network153, such as ATM, Ethernet, or Wi-Fi.

In standard network layer forwarding techniques, first network section155 and second network section 157 generally act as separate local areanetworks requiring reauthentication, and additional forwarding steps totransmit data from one section to another. However, if network sections155,157 are configured to operate using data link layer forwardingtechniques such as ATM LANE, the two network sections may communicate asif they were part of the same local area network, as described above.

To configure a network such as the one illustrated in FIG. 1B to operateusing ATM LANE, first forwarding device 163 may listen to first datalink 167 for data being sent to devices coupled to second forwardingdevice 165 through second data link 169. When such data is transmittedon first data link 167, first forwarding device 163 may transparentlyforward data to second forwarding device 165 through an ATM virtualcircuit 171 that traverses different network 153. Second forwardingdevice 165 may then transmit the data over the second data link 169 tothe destination host device.

Forwarding devices 163, 165 may be configured to forward data based onthe data link address of the destination, so each host device 159 onfirst network section 155 may transmit information to the host devices161 of second network section 157 by identifying the data link addressof the second host device as the destination address of the data.Because, according to one embodiment, forwarding may be performed usingdata link addresses and no change in network layer information occurs ina packet, devices can communicate with each other as if they werelocally connected within a transparently bridged/switched network. Sucha configuration can be used to combine network sections even when thenetwork sections use different data link protocols by converting oneprotocol to another protocol transparently.

In some implementations, first forwarding device 163 and secondforwarding device 165 may be connected through a third forwarding device173 that may be part of a different communication network 153. Forexample, using ATM LANE, a virtual circuit 171 may be establishedthrough third forwarding device 173 so that third forwarding device 173forwards information between first and second forwarding devices 163,165based on data link layer destination addresses. The third forwardingdevice 173 may be part of a network of a large communication provider,such as a telephone or cable provider, enabling first forwarding device163 to communicate over a long distance to second forwarding device 165using existing communication channels (e.g., fibers, cables, switches,etc.) of the communication provider.

It should be recognized that embodiments of the invention are notlimited to any particular arrangement and any particular configurationof forwarding devices, mobile devices, end nodes, or other networkelements.

Referring back to FIG. 1A, in some embodiments, communication network101 may also be coupled to an external network 125, such as theInternet. Devices coupled to communication network 101 may then accessdevices of external network 125. At least one edge forwarding device 127may be configured as an edge router (e.g., a router that connects alocal communication network to an external network) to couplecommunication network 101 to external network 125. Edge forwardingdevice 127 may convert received data between a communication protocolused by external network 125 and a communication protocol used bycommunication network 101 (e.g., ATM, Ethernet, Wi-Fi, etc.), if thecommunication protocols differ. The edge forwarding device may alsoprovide security features to communication network 101 such as firewallprotection.

Data received by edge forwarding device 127 and directed to adestination device coupled to communication network 101 may be directedthrough communication network 101 to the destination device. Similarly,edge forwarding device 127 may direct data transmitted from a sourcedevice coupled to communication network 101 to external network 125.

In accordance with another aspect of the present invention, a pluralityof stationary access points 131, 133, and 149 may be coupled tocommunication network 101. A stationary access point may include a wiredor wireless router, an antenna-based tower structure as described below,and/or any other device configured to provide access to communicationnetwork 101. In some embodiments, at least one first stationary accesspoint 131 may be coupled directly to communication network 101 through awired connection 139 to a forwarding device 117 coupled to communicationnetwork 101. The wired connection may include any type of mechanicalconnection such as fiber, cable, etc. Such a directly coupled firststationary access point 131 may be configured to act as a forwardingdevice of communication network 101 to couple other devices, includingother stationary access points, to communication network 101. Thisconfiguration allows communication network 101 to be accessed wherever astationary access point is located.

Various embodiments of the present invention may include at least onesecond stationary access point 133 that does not have a direct wiredconnection to communication network 101. Such second stationary accesspoint 133 may couple to communication network 101 through the at leastone first stationary access point 131 that does have a wired connection139 to communication network 101. This configuration allows multiplestationary access points to couple to communication network 101 withoutrequiring installation of direct wired connections to communicationnetwork 101 at each stationary access point. This coupling may befacilitated through wired or wireless connections between stationaryaccess points.

Each such second stationary access point 133 that is coupled tocommunication network 101 through such a first stationary access point131 may also then act as a forwarding device of communication network101 to couple other devices, including other stationary access points,to communication network 101.

A network backbone (not designated) may be comprised by stationaryaccess points 131, 133, 149 and any other forwarding devices 117, 119,123, 127 and connections 139 used to forward data among the stationaryaccess points 131, 133, 149, the servers 103, and the external network125. In some embodiments of the present invention, each device of thenetwork backbone, including stationary access points 131, 133, may beconfigured to use the ATM data link protocol and to forward data usingATM, as described above. In some implementations, the network backbonemay include a distributed network backbone (i.e., one having a pluralityof main forwarding devices directing data among the stationary accesspoints, servers, and other devices coupled to communication network101). In other implementations, the network backbone may include acollapsed backbone (i.e., one having a single main router 117 configuredto direct data among the stationary access points, servers, and otherdevices coupled to communication network 101). Use of a collapsedbackbone may simplify forwarding decisions by concentrating thedecisions into a central main router. By contrast, use of a distributedbackbone may provide a more reliable network that can accommodate one ormore router failures without a complete network failure.

In accordance with another aspect of the present invention, eachstationary access point 131, 133 may be configured to couple at leastone mobile device 137 to communication network 101.

Mobile device 137 may include a mobile access point, another type ofmobile forwarding device, or a mobile host device such as a laptop, PDA,or cell phone. In some embodiments, coupling to communication network101 may be performed through a wireless connection between at least onestationary access point 131, 133 and mobile device 137. The stationaryaccess points may allow access to communication network 101 for mobiledevices (e.g., 137) that are within communication range.

In some embodiments, before fully coupling mobile device 137 tocommunication network 101, stationary access points 131, 133 may beconfigured to authenticate mobile device 137 with authentication server105. After authenticating mobile device 137, the stationary accesspoints 131, 133 may be configured to couple mobile device 137 tocommunication network 101 (e.g., allow communication between mobiledevice 137 and communication network 101, which may includecommunication to external network 125).

To facilitate communication between mobile device 137 and communicationnetwork 101, stationary access points 131, 133 may act as forwardingdevices configured to forward data directed to and/or from mobile device137. Whenever a route to mobile device 137 changes (e.g., when mobiledevice 137 couples to communication network 101 through a new stationaryaccess point 131, 133), the new stationary access point (e.g., 131, 133)may be configured to update the forwarding information of otherforwarding devices 119, 117 and other stationary access points 131, 133coupled to communication network 101 and any external forwarding devices123 through which forwarding devices 117, 119 of communication network101 communicate, by, for example, generating and transmitting orforwarding a topology change notification (TCN) to the devices, so thatdata may be properly directed to mobile device 137. TCNs are well knownin the art of network communication.

FIG. 2 illustrates an exemplary stationary access point 201 inaccordance with another aspect of the present invention that may be usedas one of the stationary access points 131, 133, 149 illustrated in FIG.1A. In some embodiments, a stationary access point similar to that shownin FIG. 2 may be used as a primary access point to which a plurality ofsecondary access points may couple to the communication network 101, asdescribed in more detail below. The exemplary stationary access point201 comprises a support structure 207 to which a first communicationsystem and a second communication system are mounted. In one embodiment,the first communication system includes a first antenna system 203, andthe second communication system includes a second antenna system 205.Each antenna system may include one or more antennas and one or moreradio devices. In other embodiments of a stationary access point, thefirst and second communication systems may include any other type ofcommunication systems including wired or wireless communication systemsconfigured to provide full or half duplex communication, such as opticalcommunication systems or audio communication systems. The communicationsystems may be used by the stationary access point to communicate withother stationary access points and to provide access to communicationnetwork 101 to mobile devices.

The support structure 207 may include any type of support structurecapable of adequately supporting the communication systems and may bemade from any type of material including timber, fiberglass, metal, andconcrete, or combinations thereof. The support structure 207 may be usedto support other items such as advertisements (e.g., billboards),utility equipment (e.g., telephone poles), or structural elements (e.g.,a bridge). Support structure 207 may be coupled to a footing 209configured to uphold support structure 207 and any devices mounted tosupport structure 207 with the type and site of the footing beingappropriate to the climate, environment, safety guidelines, etc. of thelocation in which it is used.

In one embodiment, stationary access point 201 also may include a wiredconnection 211 to communication network 101. Wired connection 211 tocommunication network 101 may be used to transmit data betweenstationary access point 201 and communication network 101. Wiredconnection 211 may include a T1 connection, an optical fiber, or anyother wired connection configured to provide the desired bandwidthbetween communication network 101 and stationary access point 201 andcouple to the at least one mobile device 137. Other embodiments of astationary access point may alternatively include a wireless connectionto communication network 101 or connect to communication network 101through one of the other communication systems (e.g., 203). In yet afurther embodiment, a stationary access point may include both a wiredconnection 211 and a wireless connection to communication network 101.In such an embodiment, the wireless connection could be used as aback-haul network connection to communication network 101, or forredundancy in the event that communication via the wired connection isdisrupted. Whatever connection method is used, a connection tocommunication network 101 may allow stationary access point 201 and anydevices communicating with the stationary access point to couple tocommunication network 101 with data transfer rates sufficient to satisfythe desires of a user of the mobile device 137. Typical sufficient datatransfer rates to mobile device 137 may range from approximately a fewkilobytes per second to approximately many megabytes per seconddepending on the needs of the mobile device user.

In one embodiment, first antenna system 203 comprises two antennas 213,215 configured to wirelessly communicate with one or more directly orindirectly neighboring stationary access points. First antenna system203 may be used to couple the one or more neighboring stationary accesspoints to communication network 101 through first stationary accesspoint 201. Such coupling can be accomplished by forwarding data directedto communication network 101 through wired connection 211 and forwardingdata directed to the one or more neighboring stationary access points tothe first antenna system 203. A first antenna 213 of first antennasystem 203 may include a parabolic antenna, such as a 2.4 or 5.8 GHzAIRONET solid dish antenna commercially available from the CiscoCorporation, San Jose, Calif., having a main lobe oriented in a firstdirection and primarily propagating radio frequency (RF) energy toward afirst set of neighboring stationary access points. Second antenna 215 offirst antenna system 203 may include a parabolic antenna, such as a 2.4or 5.8 GHz AIRONET solid dish antenna commercially available from theCisco Corporation, San Jose, Calif., having a main lobe oriented in asecond direction and propagating RF energy primarily in the seconddirection, different than the first direction, toward a second set ofneighboring stationary access points. It should be appreciated that anyantenna type including parabolic, omnidirictional, leaky coaxial cable,or any other antenna type capable of radiating RF energy may be used forany antenna system of the present invention.

First exemplary stationary access point 201 may selectively forward datato the first set of neighboring stationary access points or the secondset of neighboring stationary access points by sending the data throughthe respective antenna 213 or 215. Each antenna 213 and 215 of firstantenna system 203 may be configured to communicate on the same ordifferent radio frequencies using the same or different communicationprotocols. For example, the first antenna may be configured tocommunicate using channel 5 of the 802.11g communication protocol (i.e.,2434 MHz) and the second antenna may be configured to communicate usingchannel 10 of the 802.11g communication protocol (i.e., 2457 MHz). Byusing such different frequencies, interference, which may occur whenneighboring antennas communicate on the same frequency, may be reduced.

Second antenna system 205 may comprise three antennas 217, 219, 221configured to communicate with at least one mobile device 137. Exemplarystationary access point 201 may forward data destined to the at leastone mobile device 137 by transmitting the data through second antennasystem 205. A first antenna 217 of second antenna system 205 may includea first parabolic antenna, such as a 2.4 or 5.8 GHz AIRONET solid dishantenna commercially available from the Cisco Corporation, San Jose,Calif., propagating RF energy primarily in a first direction along apath 129 along which at least one mobile device 137 moves. A secondantenna 219 of second antenna system 205 may also include a secondparabolic antenna, such as a 2.4 or 5.8 GHz AIRONET solid dish antennacommercially available from the Cisco Corporation, San Jose, Calif.,propagating RF energy primarily in a second direction along path 129along which at least one mobile device 137 moves. Although the first andsecond directions will generally be substantially opposite to oneanother, it should be appreciated that they will depend upon thedirection of the path along which the at least one mobile device 137moves.

First antenna 217 of second antenna system 205 may communicate with theat least one mobile device 137 when the at least one mobile device 137is traveling in the second direction toward stationary access point 201or traveling in the first direction away from the stationary accesspoint 201 and is within a communication range of first antenna 217.Second antenna 219 may communicate with the at least one mobile device137 when the at least one mobile device 137 is traveling in the firstdirection towards the stationary access point 201 or traveling in thesecond direction away from stationary access point 201 and is within acommunication range of second antenna 219.

In the illustrated embodiment, each of the first and second antennas217, 219 of second antenna system 205 propagate RF energy primarily awayfrom the first exemplary stationary access point and are disposed at aheight greater than a height of mobile device 137. This configurationmay leave an area near the support structure with a low level of signalfrom either the first of second antenna systems. The communication rangeof each of first and second antennas 217, 219 may cover an area from aminimum distance from exemplary stationary access point 201 to a maximumdistance from exemplary stationary access point 201 so that the datatransfer rate between the antenna system and the mobile device 137 is atleast a minimum level within the communication range, such as betweenapproximately a few kilobytes per second and approximately manymegabytes per second depending on the needs of the mobile device user.

A third antenna 221 of second antenna system 205 may include anomnidirectional antenna, such as an AIRONET omnidirectional mast antennaavailable commercially from the Cisco Corporation, San Jose, Calif.,configured to communicate with mobile device 137 when mobile device 137is within the communication range of third antenna 221. Thecommunication range of third antenna 221 may cover the area that isbetween the minimum distances covered by first and second antennas 217,219 of second antenna system 205. This configuration of antennas insecond antenna system 205 may allow mobile device 137 to maintaincommunication with second antenna system 205 throughout the regionbetween the exemplary stationary access point and the minimum distanceof each of the first and second antennas 217, 219 of second antennasystem 205. Thus, the communication range of the second antenna system205 may cover the region extending between the maximum distance ofantenna 217 and antenna 219, with no gap in coverage proximate to thestationary access point 201 itself. It should be appreciated that inother embodiments, the third antenna 221 may be other than anomnidirectional antenna. For example, to avoid propagating RF energy inall directions (and in particular, in directions other than toward thepath 129 along which the at least one mobile device 137 moves), it maybe desirable to use a more directional type of antenna that is capableof propagating RF energy toward the path 129, and having a beam patternthat encompasses the region between the minimum distances of antenna 217and 219. A stationary access point configured in accordance with theseembodiments of the present invention and in accordance with previouslydiscussed aspects of the present invention may provide sufficient datatransfer rates between the mobile device 137 and a communication networkwhenever the mobile device is within a communication range of one of aplurality of stationary access points that may be arranged across alarge geographical area.

To facilitate communication among antenna systems 203, 205 andcommunication network 101, each antenna system may be connected togetherby a wired bus 235 that also connects to wired connection 211. When datais received by one antenna system, it may be transmitted to anotherantenna system or to wired connection 211 through wired bus 235.Similarly when data is received through wired connection 211, it may beforwarded to one or more of the antenna systems through wired bus 235.

First antenna system 203 may include first and second forwarding element223, 225. Each of the forwarding elements 223, 225 may maintainforwarding information for a plurality of devices coupled tocommunication network 101, including mobile device 137 and anyneighboring stationary access points. When data is received by firstantenna 213 of first antenna system 203 (e.g., from the first set ofneighboring stationary access points), first forwarding element 223 mayforward the data to either second antenna 215 of first antenna system203 to be transmitted to the second set of neighboring stationary accesspoints, to second antenna system 205 to be transmitted to the at leastone mobile device 137, or to wired connection 211 to be transmitted tocommunication network 101. Similarly, when data is received by secondantenna 215 of first antenna system 203 (e.g., from the second set ofneighboring stationary access points), second forwarding element 225 mayforward the data to either first antenna 213 of first communicationsystem 203 to be transmitted to the first set of neighboring stationaryaccess points, to second antenna system 205 to be transmitted to the atleast one mobile device 137, or to wired connection 211 to betransmitted to communication network 101. Decisions of where to forwardthe data may be made based on forwarding information maintained byforwarding elements 223, 225. Such forwarding information may include,for example, a well-known forwarding table. After making the forwardingdecision, the data may then be transmitted through wired bus 235.

In one embodiment, second antenna system 205 may include a thirdforwarding element 227. Similar to first and second forwarding elements223, 225 of first antenna system 203, third forwarding element 227 ofsecond antenna system 205 maintains forwarding information for aplurality of devices coupled to communication network 101. When data isreceived by second antenna system 205, third forwarding element 227forwards the data to first antenna system 203 for transmission to aneighboring stationary access point or to direct connection 211 fortransmission to communication network 101. Decisions of where to forwarddata may be made based on forwarding information maintained by thirdforwarding element 227.

In some embodiments, the forwarding elements of the antenna systems 203,205 may include the radio devices coupled to the antenna systems. Forexample, a radio device coupled to first antenna system 203 of the firstcommunication system may provide input to first antenna 213 andforwarding functionality for incoming and outgoing information, asdescribed above. In some implementations, an AIRONET wireless accesspoint available commercially from the Cisco Corporation, San Jose,Calif., may be used as a radio device with such forwarding capabilitiesfor the antenna systems.

A fourth forwarding element 229 may be coupled to wired connection 211.Similar to forwarding elements 223, 225, 227 of first and second antennasystems 203, 205, fourth forwarding element 229 may maintain forwardinginformation for a plurality of devices coupled to communication network101. When data is received through wired connection 211, fourthforwarding element 229 forwards the data to first antenna system 203 fortransmission to a neighboring stationary access point or to secondantenna system 205 for transmission to mobile device 137. Decisions ofwhere to forward data may be made based on forwarding informationmaintained by the fourth forwarding element.

In an alternative embodiment of a stationary access point, eachcommunication system and the wired connection may be treated as a singlecommunication system having only a single forwarding element. Anyinformation received through any antenna may be transmitted to thesingle forwarding element. The single forwarding element may thendetermine where the received information should be directed based onmaintained forwarding information. For example, the single forwardingelement may forward the data to the first or second antenna of firstantenna system 203 for transmission to a neighboring stationary accesspoint, to second antenna system 205 for transmission to mobile device137, or to wired connection 211 for transmission to communicationnetwork 101.

In accordance with one embodiment of the present invention, a solarpower source 231 and battery 233 may be coupled to support structure 207of the first exemplary stationary access point. The solar power source231 may be configured to supply power to the stationary access point asneeded by the devices coupled to the stationary access point 201,including first and second antenna system 203, 205. The battery 233 maybe configured to store excess power generated by solar power source 231to supply power to stationary access point 201 when the solar powersource 231 is unable to supply sufficient power (e.g., at night orduring inclement weather). Using a solar power source 231 allowsdisposing of stationary access points in locations where power lines arenot readily available or may require great cost to install. In otherembodiments, a wired connection to an external power supply may power astationary access point. In still other embodiments, multiple powersources (e.g., solar, battery, wired, and wind) may be used.

FIG. 3 illustrates another embodiment of a stationary access point 301having wired connections 303, 305 to each of its neighboring stationaryaccess points that may be used as one or more of the stationary accesspoints disposed along or adjacent to the path of FIG. 1A. A firstcommunication system is a first antenna system 307 of the secondexemplary stationary access point 301. First antenna system 307 may beused to communicate with the at least one mobile device 137 and may besubstantially similar to second antenna system 205 of previouslydescribed stationary access point 201. In other embodiments, the firstcommunication system may include any other type of communication deviceincluding a wired or wireless communication device configured to providefull or half duplex communication. For example, the first communicationsystem may include an optical or audio based communication device.

Unlike the previously described stationary access point 201, thestationary access point 301 of FIG. 3 does not include an antenna systemconfigured to communicate with neighboring stationary access points.Rather, this embodiment of a stationary access point 301 may communicatewith neighboring stationary access points by wired connection 303, 305to the neighboring stationary access points. Such wired connections 303,305 may increase the bandwidth of communication between neighboringstationary access points compared to neighboring stationary accesspoints communicating using wireless connections. This increase inbandwidth may allow larger amounts of data to be transferred morequickly among the stationary access points and to mobile devices coupledto communication network 101 through such stationary access points. Asdescribed above, wired communication may be by any means including amechanical connection, such as a fiber, wire, coaxial cable, etc.

In one embodiment, second exemplary stationary access point 301 may notinclude a wired connection directly to communication network 101.Instead, second exemplary stationary access point 301 may be coupled tocommunication network 101 through one of the neighboring stationaryaccess points. Such a stationary access point that couples to thecommunication network 101 through a neighboring stationary access pointmay be referred to as a secondary stationary access point, and theaccess point through which the secondary stationary access point couplesmay be referred to as a primary stationary access point. Such aconfiguration reduces the number of direct connects to the communicationnetwork that are needed to expand the area covered by the plurality ofstationary access points. New stationary access points can be added bysimply connecting them to the existing stationary access points eitherby wired connections as in the embodiment of FIG. 3 or by wirelessconnections such as the ones described with respect to the firstcommunication system of FIG. 2.

FIG. 4 illustrates yet another example of an arrangement of an exemplarystationary access point 401. As illustrated, in some embodiments,stationary access points may be positioned near an obstruction 403 thatmay obscure wireless transmission in one or more directions. Such anobstruction 403 may include, for example, a bridge, tunnel, or othergeographic structure. As illustrated in FIG. 4, a stationary accesspoint may be arranged to provide access to communication network 101despite such an obstruction.

As illustrated, some embodiments of a stationary access point mayinclude multiple supports 405 (e.g., two as shown in FIG. 4). One ormore antenna systems 407 may be attached to each of the multiplesupports 405. The supports 405 may be positioned on opposing sides ofthe one or more obstructions 403 and the antenna systems 407 may bearranged to face substantially away from the obstruction 403 to providenetwork access to mobile devices on respective sides of the obstruction403. Between the supports 405, an intermediate antenna system 409 may bepositioned to provide network access to mobile device there between. Forexample, in some implementations, the intermediate antenna system 409may include a length of leaky coaxial cable disposed between the poles.The leaky coaxial cable may be connected to communication systems of oneor more of the respective poles to provide a communication signal tomobile devices that are within range between the poles, such astraveling over a bridge, through a tunnel, or otherwise near theobstruction. In some implementations, leaky coaxial cable may include acoaxial cable with a relatively low attenuation per foot (e.g., Radiaxcable from the Andrew Corporation of Westchester, Ill.).

It should be recognized that the previously described example stationaryaccess points are given as non-limiting examples only. In otherembodiments any type or arrangement of stationary access point may beused. Such access points are not limited to any number or type ofantennas or antennas systems.

According to various aspects of the present invention, the plurality ofstationary access points 131, 133 may be disposed along or adjacent topath 129 traveled by a vehicle 501 as shown in FIG. 5 and FIG. 1A. Inaccordance with aspects of the present invention, vehicle 501 mayinclude any vehicle capable of transporting the at least one mobiledevice 137 from one location to another. In various embodiments, vehicle501 may be configured to transport a plurality of mobile devices (e.g.,137, 507, 509, 511, 513) and mobile device users along the path so thatthe plurality of mobile devices move relative to the stationary accesspoints 131, 133. In the illustrated embodiment of FIG. 5, vehicle 501includes a train that moves along fixed train tracks (i.e., the path129). In other embodiments, a vehicle (e.g., 501) may include a boattraveling along a path (e.g., 129) of a water way (e.g., a shippinglane, ferry rout, etc.) or a bus or subway traveling along the path(e.g., 129) from one location to another. The mobile devices may includevarious computing devices such as cell phones, personal digitalassistants, laptop computers, etc. that are used by passengers travelingaboard the vehicle, such as daily commuters on their way to and fromwork. The path 129 may include a fixed path or a nearly fixed path, suchas a roadway, a track, a ferry route, or a shipping lane. The path mayspan a long distance of many kilometers.

In accordance with some embodiments, the path 129 may include a tunnelportion in which a supporting structure 207 is unavailable and/ordifficult or costly to install. In such environments, a communicationdevice capable of communicating with the mobile device may be attachedto a portion of the tunnel wall or any other nearby existing structure(e.g., canyon wall). Such a communication device may include one or moreparabolic antennas as described in the second antenna system of thefirst exemplary stationary access point above. A plurality of suchcommunication devices may be wired together along the length of thetunnel portion or may communicate wirelessly through a second set ofcommunication devices, such as the previously described first antennasystem of the exemplary stationary access point illustrated in FIG. 2.

Alternatively, other embodiments may use at least one leaky coaxialcable in the tunnel portion as an antenna to couple the mobile device137 to communication network 101 when the mobile device 137 is in thetunnel portion. For example, the leaky coaxial cable may be coupled to atunnel forwarding device that is coupled to communication network 101.The tunnel forwarding device may broadcast data along and receive datafrom the leaky coaxial cable. The tunnel forwarding device mayauthenticate mobile device 137 with authentication server 105 whenmobile device 137 first attempts to communicate with communicationnetwork 101 and act as a root device (i.e. a forwarding device thatmaintains, at least for a certain duration of time, authenticationinformation of mobile device 137, as will be described in more detailbelow) to mobile device 137. The leaky coaxial cable may be arrangedalong or adjacent to a length of the tunnel section (e.g., attached to atunnel wall or ceiling along the length of the tunnel). If necessary,multiple leaky coaxial segments may be used (e.g., in an extended tunnelsuch as the tunnel under the English Channel, etc.). Data may then betransmitted to mobile device 137 as energy radiating from the leakycoaxial cable along the length of the tunnel section after transmissionfrom the tunnel forwarding device. Likewise, energy radiated by mobiledevice 137 may be received by the leaky coaxial cable and transmitted tothe tunnel forwarding device. The leaky coaxial cable may be any coaxialcable having one or more portions of shielding removed along the lengthof the coaxial cable, such as a cable with a plurality of unshieldedapertures, a cable with an unshielded slit, etc.

FIGS. 6A and 6B illustrate example leaky coaxial cable hangers that maybe used in various embodiments to connect coaxial cable to a desiredsurface. The leaky coaxial cable hanger of FIG. 6A may be attacheddirectly to a wall, ceiling, flooring, or other surface as desired.Similarly, the leaky coaxial cable hanger of FIG. 6B may also be hungfrom any surface as desired. The hanger of FIG. 6A may be used insituations where less clearance is available for a hanger, such as in asmall tunnel. The cable may be disposed through cable hole 601 in eitherof the illustrated hangers.

Returning to refer to FIG. 5, various embodiments of the presentinvention may include multiple vehicles or a vehicle comprising aplurality of vehicle portions 503, 505. Each vehicle or vehicle portionmay be configured to transport a plurality of mobile devices (e.g., 137,507, 509, 511, 513) and users of mobile devices along path 129. Forexample, the train of FIG. 5 comprises a plurality of cars including acafe car 503 and a passenger car 505. Various other embodiments mayinclude a caravan of busses, cars, boats, or other vehicles.

In one aspect of the present invention, each stationary access point131, 133 may be configured to allow wireless communication with the atleast one mobile device 137 when mobile device 137 is in a communicationrange of the stationary access point. The stationary access points(e.g., 131, 133) may be arranged along the path 129 such that mobiledevice 137 is in the communication range of at least one stationaryaccess point 131, 133 at all times as it travels from one end of path129 to another end of path 129. Such a configuration allows a mobiledevice to travel the path and maintain communication with at least onestationary access point and communication network 101.

In some embodiments, the stationary access points may be configured in aprimary-secondary configuration. For example, a primary pole, such asone illustrated in FIG. 2, may feed communication signals to a pluralityof secondary poles. The primary and secondary poles in a respectivegroup may be grouped together, for example, using a wired connection.The primary poles, however, may be connected through wirelesscommunication. Other arrangements may be used.

For security purposes, first stationary access point 131 to which mobiledevice 137 attempts to connect may be configured to allow access tocommunication network 101 only after mobile device 137 has beenauthenticated. Mobile device 137 may request authentication when itenters a communication range of first stationary access point 131. Firststationary access point 131 may authenticate mobile device 137 throughauthentication server 105 by transmitting an authentication request toauthentication server 105 through communication network 101. When mobiledevice 137 moves from the communication range of first stationary accesspoint 131 to the communication range of second stationary access point133, mobile device 137 may request authentication with second stationaryaccess point 133. Similar to the first stationary access point, thesecond stationary access point 133 may communicate with authenticationserver 105 to authenticate mobile device 137 before allowing mobiledevice 137 access to communication network 101. By requiringauthentication, the stationary access points 131, 133 prevent unwantedor untrusted devices from coupling to communication network 101.

Some embodiments of the present invention may not require authenticationat all. For instance, some implementations may use wired equivalentprivacy (WEP) encryption to prevent unwanted or untrusted devices fromaccessing communication network 101. In one such example, a WEP key maybe shared with each trusted mobile device, and only the devices knowingthe WEP key may then be allowed to couple to the communication network101. It should be appreciated that various embodiments of the inventionmay use authentication or not, either alone or in connection with othermethods, and the invention should not be limited to any particular typeof authentication or combination of methods.

Once a mobile device 137 is authenticated to the second stationaryaccess point 133, the second stationary access point may record theauthentication information in an association table. The secondstationary access point 133 may remove the recorded information after aset timeout period. While the information is in the association table,mobile device 137 may be allowed to couple to communication network 101through the second stationary access point 133 without requiringreauthorization. In some embodiments, the association table may recordauthentication information of mobile device 137 based on a physicaladdress of a communication device of mobile device 137 (i.e., the MACaddress of a wireless adapter of the mobile device 137 may be recordedin an association table to indicate that the mobile device 137 isauthenticated).

A stationary access point that records the authentication information ofan authenticated mobile device 137, for at least a minimum time period,may, in the art, be called a root device. Conversely, a mobile devicethat was authenticated but does not record any authenticationinformation and acts as a client of the root device may be called anon-root device. As described above, since stationary access points mayhave multiple communication devices, the root/non-root distinction maybe applied at the communication device level. For example, the mobiledevice 137 may be only authorized to couple to the communication network101 through a first communication device of a plurality of communicationdevices comprising a stationary access point (e.g., the second antennasystem 205 of the first exemplary stationary access point 201). In thatcase, the first communication device may be a root device for the mobiledevice 137. In some cases, as discussed below, the mobile device maycomprise a plurality of communication devices including a non-rootcommunication device to communicate with the root communication deviceof the stationary access point and root communication devices tocommunicate with non-root communication devices of other mobile devices.

Because root devices record the authentication information of otherdevices, the other devices may not need to be reauthenticated when theyattempt to communicate with the root device after a firstauthentication. In some instances, the root devices may be configured torecord the authentication information only for some predetermined periodof time or timeout period when communication with the other devices isexpected. In some implementations, the predetermined period of time maybe a number of days such that a user of a mobile device that travels thepath regularly needs to be reauthenticated only after an extended breakin use, such as a vacation.

In some embodiments, authentication may delay mobile device 137 fromcoupling to communication network 101 because mobile device 137 may bedenied access to communication network 101 until mobile device 137 isauthenticated. If the first stationary access point 131 and the secondstationary access point 133 are arranged such that their respectivecommunication ranges do not overlap, mobile device 137 may be leftwithout access to communication network 101 when it moves from thecommunication range of first stationary access point 131 to thecommunication range of second stationary access point 133 while secondstationary access point 133 waits for authentication of mobile device137.

In various embodiments of the present invention, the plurality ofstationary access points may be arranged such that each stationaryaccess point's communication range overlaps with the communication rangeof at least one other stationary access point so that the mobile device137 does not experience access interruption as it moves between thefirst and second stationary access points 131, 133 of the plurality ofstationary access points because of the authentication process. Theoverlap of communication ranges may be large enough so thatauthentication of the mobile device 137 by the second stationary accesspoint 133 may be completed before the mobile device 137 moves out of thecommunication range of the first stationary access point 131. Theoverlap in communication range may vary based on the speed at which themobile device is traveling and the time needed for performing theauthentication process.

As vehicle 501 travels along path 129, line of sight may be maintainedbetween mobile device 137 and a communication system of stationaryaccess points (e.g., 131, 133) communicating with mobile device 137 toimprove communication range. If the communication system includes anantenna system, obstruction of line of sight may diminish thereliability of services and the communication range of the stationaryaccess points 131, 133. If the communication system includes an opticalsystem, the obstruction of line of sight may completely endcommunication between mobile device 137 and stationary access points131, 133. To maintain line of sight, the communication system of thestationary access point that is communicating with the mobile device 137(e.g., the second antenna system of the first stationary access point)may be disposed at a sufficient height so that vehicle 501 does notobstruct the line of sight between the communication system and mobiledevice 137. In some implementations, the sufficient height may be atleast as great as the tallest portion of the vehicle. In someimplementations where the communication system includes an antennasystem, the antenna system may be arranged such that less thanapproximately 40% of the radiation pattern of the antenna system isblocked by vehicle 501 as it travels along path 129.

To maintain line of sight as the vehicle 501 travels along a curve 141of path 129, more stationary access points may be needed than tomaintain line of sight along a straight portion 147 of path 129. Thismay be particularly true if the stationary access points are disposedalong an inner portion of curve 141 so that they are passed quickly byvehicle 501 as it travels along curve 141. In one embodiment, to improvethe line of sight of each stationary access point disposed along a curve(e.g., 141) in path 129, stationary access points may be disposed alongor adjacent to the outer portion of curve 141. Disposing stationaryaccess points along or adjacent the outer portion of the curve 141 mayensure that as the vehicle 501 traverses the curve 141, it is withincommunication range of at least one other stationary access point.

Furthermore, if vehicle 501 is moving quickly along curve 141, mobiledevice 137 may quickly move from the communication range of the firststationary access point 131 to the communication range of the secondstationary access point 133. The time needed to authenticate mobiledevice 137 may be longer than the time in which the mobile device iswithin the overlapping communication ranges of the first and secondstationary access points thereby potentially causing a break in networkaccess.

To facilitate faster authentication times, according to one embodiment,the first and second stationary access points 131, 133 and any otherstationary access points along curve 141 may be combined into one ormore stationary access point groups 143, as shown in FIG. 1A. Thestationary access point group 143 may be coupled to a stationary accesspoint group controller 145. According to one embodiment, groupcontroller 145 may be configured to provide a local authentication cachethat stores authentication information requested and received by anystationary access point in stationary access point group 143. The localauthentication cache may remove this information after a timeout periodhas passed, which may depend, for example, on the amount of memory inthe cache. Authentication by one of the stationary access points ofstationary access point group 143 then may only involve authenticationserver 105 if the authentication cache does not contain the requestedauthentication information. Once authenticated, as the vehicle 501 moveswithin the communication range of other stationary access points thatare members of the group 143, the mobile device 137 may be authenticatedby reference to the cached information, thereby eliminating the need toauthenticate with the server 105. In accordance with one embodiment, theamount of memory of the cache may be sufficient to permit theinformation to remain for several days, such that a commuter that usesthe same transportation need not be re-authenticated unless he or she isaway for an extended period of time (e.g., a vacation).

In one embodiment, group controller 145 may include a wireless LANcontext communication protocol (WLCCP) controller coupled to each of thestationary access points in the stationary access point group 143. Insome implementations, the WLCCP controller may include a AIRONET accesspoint, available commercially from the Cisco Corporation, San Jose,Calif., coupled to the stationary access points of the group. The groupcontroller 145 may facilitate low latency authentication of the mobiledevice 137. Authentication may be provided to the stationary accesspoints of the stationary access point group 143 in less thanapproximately two milliseconds if the requested authenticationinformation is cached.

It should be appreciated that stationary access points may fail overtime, leaving gaps of coverage along the path 129, which may also causebreaks in network access for the mobile device. To help prevent suchgaps in coverage, in some embodiments of the present invention, theplurality of stationary access points may be arranged along path 129 sothat coverage along path 129 is redundant. For example, first stationaryaccess point 131, second stationary access point 133, and a thirdstationary access point 149 may be arranged so that the first and thirdstationary access 131, 149 points have a combined communication rangethat covers the communication range of the second stationary accesspoint 133 and a sufficient overlap so that authentication by the thirdstationary access point 149 may complete before mobile device 137 leavesthe communication range of the first stationary access point 131.

In such an arrangement, the second stationary access point 133 may failwithout leaving a gap in coverage between the first and third stationaryaccess points 131, 149. Therefore, even if the second stationary accesspoint 133 is the closest stationary access point to mobile device 137,there may be no interruption in access to communication network 101 asmobile device 137 moves from the communication range of first stationaryaccess point 131 to the communication range of third stationary accesspoint 149, even if secondary stationary access point 133 is notoperating or if communication between the mobile device 137 and thesecondary stationary access point 133 is otherwise disrupted.

In one embodiment, mobile device 137 may be configured to change thestationary access point through which mobile device 137 couples tocommunication network 101 as vehicle 501 travels path 129. When mobiledevice 137 is in communication range of a plurality of stationary accesspoints, mobile device 137 may be configured to couple to communicationnetwork 101 through the stationary access point providing the strongestor one of the stronger communication signal strengths at a currentlocation of the of mobile device 137. The signal strength may bemeasured by the well-known received signal strength indicator (RSSI).

To facilitate a quick transition of the mobile device from coupling tocommunication network 101 through first stationary access point 131 tocoupling through second stationary access point 133, mobile device 137may be configured to authenticate with the second stationary accesspoint 133 while mobile device 137 is still coupled to communicationnetwork 101 through the first stationary access point 131 and prior tomobile device 137 being configured to couple to communication network101 through second stationary access point 133. For example, mobiledevice 137 may be configured to authenticate with second stationaryaccess point 133 when the signal strength of second stationary accesspoint 133 is still less than the signal strength of first stationaryaccess point 131.

In some implementations, mobile device 137 may be configured toauthenticate with second stationary access point 133 relatively soonafter mobile device 137 enters the communication range of secondstationary access point 133. Specifically, the mobile device 137 mayauthenticate with the second stationary access point 133 when the signalstrength of the second stationary access point 133 is approximately halfthe signal strength of the first stationary access point 131.

In one implementation, mobile device 137 may be configured toauthenticate with secondary stationary access point 133 by wirelesscommunication to secondary stationary access point 133. For example,mobile device 137 may transmit an authentication request to secondarystationary access point 133 using a wireless communication system, asdescribed below. In one implementation, mobile device 137 may beconfigured to authenticate with secondary stationary access point 133through wireless communication with first stationary access point 131.For example, mobile device 137 may transmit an authentication requestfor second stationary access point 133 to first stationary access point131 using a wireless communication system, as described below. Firststationary access point 131 may receive the authentication request andforward the request to second stationary access point 133 (e.g., throughthe backbone). Second stationary access point 133 may authenticatemobile device 137, as described above, and transmit an authenticationresponse to mobile device 137 though first stationary access point 131.

In one embodiment, first stationary access point 131 may communicate anauthentication request for second stationary access point 133 to secondstationary access point 133 using a data link layer address of secondstationary access point 133. In one embodiment, such communication mayoccur when first stationary access point 131 and second stationaryaccess point 133 may be geographically distant or separated by one ormore external communication networks or other network layer barriers(e.g., router). For example, the first and second stationary accesspoint may communicate using ATM LANE such that they may communicate withone another using data link layer addresses even over network barriersand large distances, as described above.

While the authentication occurs and after the authentication finishes,the mobile device 137 may be configured to continue coupling to thecommunication network 101 through the first stationary access point 131.Mobile device 137 may be configured to stop coupling to thecommunication network 101 through the first stationary access point 131and begin coupling to the communication network 101 through the secondstationary access point 133 at one of the later of when theauthentication completes, when the strength of the communication signalreceived by mobile device 137 from the second stationary access point133 exceeds the strength of the communication signal received by themobile device 137 from the first stationary access point 131, or both.

In one aspect of the present invention, the at least one mobile device137 communicating with stationary access points may include a mobileaccess point (also referenced herein as 137) configured to couple aplurality of other mobile devices 507, 509, 511, 513 to thecommunication network 101 through the plurality of stationary accesspoints. The mobile access point 137 may provide access to communicationnetwork 101 to each of the plurality of mobile devices 507, 509, 511,513 as mobile access point 137 travels along the path near or adjacentto stationary access points 131 and 133, for example while on a vehicle(e.g., 501).

In some embodiments, the stationary access points may be configured toauthenticate the mobile access point 137 before allowing it to couplethe other mobile devices 507, 509, 511, 513 to the communicationnetwork. The authentication may be performed through communication withthe authentication server 105 or group controllers as described above.In some implementations, the authentication may be based on a physicaladdress (e.g., MAC address) of a communication system of the mobileaccess point 137. Such authentication based on physical addresses allowsthe mobile access point to authenticate without a user or administratorentering a password or other login information.

The mobile access point 137 may be configured to communicate with theplurality of stationary access points using any communication protocol.If the network backbone is configured to communicate using ATM, mobileaccess point 137 may be configured to communicate with the plurality ofstationary access points using ATM as well. Such a configuration mayallow data to be forwarded through the plurality of stationary accesspoints to mobile access point 137 without conversion from one protocolto another or reference to the network layer destination address of thedata.

In one embodiment, mobile access point 137 may be configured to couple aplurality of mobile host devices 507 traveling along with the mobileaccess point 137 to communication network 101. The plurality of hostdevices 507 may include laptop computers, mobile phones, PDAs, or anyother computing device configured to communicate over a computernetwork, such as those used by passengers of a vehicle.

In one embodiment, mobile access point 137 may be configured to allow atleast one host device of the plurality of host devices 507 to couple tothe communication network 101 after the mobile access point 137authenticates the one host device with the authentication server 105.When the one host device attempts to couple to communication network 101through the mobile access point 137, a user of the one host device maybe required to provide login information such as a username and passwordto complete authentication. After authentication, the mobile accesspoint 137 may couple the one host device to communication network 101through one of the stationary access points. In some embodiments of thepresent invention, mobile access point 137 may act as a root device forthe one host device (i.e., the mobile access point may record theauthentication information of the one host device). In such embodiments,when mobile access point 137 moves to couple itself and the one hostdevice to the communication network 101 through a different stationaryaccess point, only mobile access point 137 may be required toauthenticate with the different stationary access point. Because mobileaccess point 137 records that one host device has already beenauthenticated, no reauthentication may be needed between the mobileaccess point and the plurality of host devices 507. Such a configurationreduces the amount of authentication requests sent to the authenticationserver 105 each time mobile access point 137 moves to couple to thecommunication network 101 through a new stationary access point therebyallowing faster authentication of mobile access point 137.

The plurality of host devices 507 coupled to the communication network101 through the mobile access point 137 may request IP addresses fromthe DHCP server 109 and access devices coupled to the communicationnetwork 101 and resources of the communication network 101. Mobileaccess point 137 may be configured to transmit forwarding information tocommunication network 101 for each of the plurality of host devices 507so that other devices coupled to the communication network 101 maycommunicate with the host devices 507. The forwarding information mayinclude the IP address of each of the host devices 507 and/or thephysical addresses of each of the host devices 507.

Each time the mobile access point 137 moves to couple the host devices507 to the communication network 101 through a different stationaryaccess point, forwarding information may be transmitted through thecommunication network 101 to update the forwarding information of theother devices, including the forwarding devices, stationary accesspoints, and servers, coupled to the communication network 101. When theother devices receive the updated forwarding information they may recordthe updated forwarding information to facilitate proper forwarding ofdata to the host devices 507 in the future. The forwarding informationmay include an identification of the port on which information destinedfor the host devices 507 should be transmitted in order to reach thehost devices. The identification of the port may include receipt of theupdated forwarding information on the port. When the other devicesreceive information destined for one of the host devices, they canreference this updated forwarding information and transmit data to theproper port. By so maintaining the forwarding information each time themobile access point 137 moves, the host devices 507 may move along thepath 129 without the need to obtain a new address to receive datadestined for the host devices 507.

Communication between the mobile access point 137 and the host devices507 may occur using any communication protocol known to both hostdevices 507 and mobile access point 137. If the network backbone andmobile access point 137 are configured to communicate using ATM, thehost devices 507 may be configured to communicate with the mobile accesspoint 137 using ATM as well. Such a configuration may allow data to beforwarded through the communication network 101, the stationary accesspoints, and the mobile access point 137 to the host devices 507 withoutconversion from one protocol to another or reference to a network layerdestination address of the data. Many host devices 507, however, may notbe configured to use an ATM connection. The mobile access point 137 maybe configured to communicate with these host devices 507 using any othercommunication protocol, such as Ethernet or Wi-Fi. Communication betweenmobile access point 137 and host devices 507 may be wired, wireless or acombination of wired and wireless. It should be recognized thatinformation may be transmitted from one device (e.g., forwarding device,mobile device, etc.) to another device using any number of formatsand/or protocols. Accordingly, as used herein, the expression “arepresentation of at least a portion of data” received by a deviceshould be understood to refer to the underlying data received by adevice, regardless of the formatting or other protocol informationassociated with that data.

In one embodiment, the mobile access point 137 may not directlycommunicate with host devices 507. Instead, a repeater 517 may beconnected to the mobile access point 137 and direct data between themobile access point 137 and the host devices 507. Repeater 517 may thenrepeat the received information either through wired or wirelesscommunication methods to host devices 507.

In some embodiments of the present invention, at least one mobileforwarding device 509 may couple to the communication network 101through the mobile access point 137. Mobile forwarding device 509 mayinclude a router, switch, bridge, and/or repeaters configured to allowother mobile forwarding devices and/or mobile host devices 511 to coupleto the communication network 101 through the mobile access point 137.Mobile forwarding device 509 may be used to extend the range of themobile access point 137.

Mobile forwarding device 509 may be configured to communicate withmobile access point 137, other mobile forwarding devices, and mobilehost devices 511 using any communication protocol. If the networkbackbone and the mobile access point are configured to communicate usingATM, mobile forwarding device 509 may be configured to use ATM as well.Such a configuration may allow data to be forwarded through thestationary access points to the mobile access point 137 and then tomobile forwarding device 509 without conversion from one protocol toanother or reference to a network layer destination address of the datato provide a higher speed forwarding of data to and from mobileforwarding device 509.

Before a mobile forwarding device (e.g., 509) couples to thecommunication network 101 though the mobile access point 137, the mobileaccess point 137 may first authenticate the mobile forwarding devicebased on a physical address of the mobile forwarding device 509. Eachmobile forwarding device (e.g., 509) may be configured to authenticateother mobile forwarding devices and mobile host devices 511 beforecoupling the other mobile forwarding devices and mobile host device 511to the communication network 101 through mobile access point 137.

Mobile forwarding device 509 may be configured to act as a root devicefor other mobile forwarding devices, such as those shown coupled toother cars of the train depicted in FIG. 7. The mobile forwarding device509 may also be configured to act as a root device to the mobile hostdevices 511 coupled to mobile access point 137 through the mobileforwarding device 509. In such an implementation, the mobile forwardingdevice 509 may maintain authentication information for these othermobile forwarding devices and mobile host devices 511 so thatreauthentication of mobile forwarding devices and host devices may notbe required as the mobile access point 137 moves to couple to thecommunication network 101 through a new stationary access point.

In one embodiment, mobile forwarding device 509 may include a repeatercoupled to the passenger car 505 of vehicle 501 that communicateswirelessly with the mobile access point 137 coupled to the cafe car 503of vehicle 501. Further, mobile forwarding device 509 may include arepeater to communicate with mobile host devices 511 within thepassenger car. If the vehicle included other passenger cars, such ascars 705 and 707 of FIG. 7, another mobile forwarding device 701, 703may be coupled to each car, as is shown in FIG. 7. Mobile forwardingdevices 701, 703 couple host devices 709, 711 to the communicationnetwork 101. Mobile forwarding devices 701, 703 in passenger carsfarther away from the mobile access point 137 may communicate with themobile access point 137 through mobile forwarding devices (e.g., 509)closer to the mobile access point 137 or communicate directly with themobile access point 137, as is illustrated in FIG. 7.

The mobile access point 137 may be configured with a plurality ofcommunication systems similar to the communication systems of thestationary access point described above. The plurality of communicationsystems may include one or more wired communication systems. Theplurality of communication systems may include one or more wirelesscommunication systems configured to provide full or half duplexcommunication, such as optical or RF based communication systems. Afirst communication system may be configured to communicate with theplurality of stationary access points to couple the mobile access point137 to the communication network 101. A second communication system ofthe mobile access point 137 may be configured to communicate with one ormore host devices 507, 513 to couple the host devices 507, 513 to thecommunication network 101. A third communication system may beconfigured to communicate with one or more mobile forwarding devices(e.g., 509) to couple the mobile forwarding devices to the communicationnetwork 101. One or more of the communication systems of the mobileaccess point 137 may be an antenna system or other wirelesscommunication system. The mobile access point 137 may include aforwarding system configured to forward data received by onecommunication system to another communication system to reach thedestination of the data. The plurality of communication systems may beconnected together with a wired connection. The forwarding of data maybe performed based on maintained forwarding information.

Such a configuration allows the mobile access point to communicate withthe stationary access points through one dedicated communication device,the host devices through another, and the repeaters through a third.Each communication device may communicate using the same or a differentcommunication protocol on the same or a different channel. If thedevices each communicate using different frequencies, the entirebandwidth of each communication device may be available to communicatewith the set of devices assigned to the communication device (e.g., thecommunication device used to communicate with the stationary accesspoints may not reduce the bandwidth or interfere with the communicationdevice used to communicate with the host devices).

The mobile forwarding device 509 may also include a plurality ofcommunication systems. The plurality of communication systems mayinclude one or more wired communication systems. A first communicationsystem may be configured to communicate with the mobile access point137. A second communication system may be configured to communicate withthe mobile host devices 511. A third communication system may beconfigured to communicate with one or more other mobile forwardingdevices. One or more of the communication systems of the mobileforwarding device 509 may be an antenna system or other wirelesscommunication system configured to provide full or half duplexcommunication. The mobile forwarding device may include a forwardingsystem configured to forward data received by one communication deviceto another communication device to reach the destination of the data.The plurality of communication systems may be connected together with awired connection. The forwarding of data may be performed based onmaintained forwarding information.

It should be recognized that the above described configuration of mobileaccess points and mobile forwarding devices is given as an example onlyand that any other desired configuration may be used in otherembodiments. For example, in some embodiments, no mobile forwardingdevice may be used, but rather, mobile devices may couple to mobileaccess points directly. In still other embodiments, each portion of avehicle (e.g., car of a train) may include a separate mobile accesspoint rather than a mobile forwarding device. Such an arrangement may bebeneficial, for example, if distance between portions of a vehicle aretoo large and/or line of sight between portions of a vehicle areotherwise obstructed and are not sufficient for wireless transmissionfrom a mobile forwarding device in one portion of the vehicle to amobile access point in another portion of the vehicle (e.g., such aswhen going through tunnels, around curves, etc.).

In one aspect of the present invention, a monitoring server 113 may becoupled to the communication network 101. The monitoring server 113 maybe configured to determine the geographic location of the vehicle 501,the mobile access point 137, or a mobile host device 511 coupled to thecommunication network 101 traveling along with the vehicle 501. In oneembodiment of the present invention, to facilitate this determination, aglobal positioning device may be coupled to the mobile access point 137.The monitoring server 113 may receive information from the globalpositioning device identifying the position of the mobile access point137. Since the mobile access point and host devices move along with thevehicle 501, the position of the mobile access point is indicative ofthe position of the vehicle 501 and the host devices.

In another embodiment of the present invention, the geographic positionof each of the stationary access points may be known to the monitoringserver 113 (e.g., they may be determined at the time of installation andinput to the monitoring server 113). The monitoring server 113 may beconfigured to monitor which stationary access points are communicatingwith the mobile access point 137. In one implementation, each stationaryaccess point may periodically transmit information to the monitoringserver 113 indicating whether the stationary access point iscommunicating with the mobile access point 137. In otherimplementations, each stationary access point may be configured tonotify the monitoring server 113 whenever the mobile access point 137begins or stops communicating with the stationary access point. Themonitoring server 113 may approximately determine the location of themobile access point 137 based on the stationary access points with whichthe mobile access point 137 is communicating. For example, themonitoring server may approximate the location of the mobile accesspoint 137 to be at the known location of the second stationary accesspoint 133 when the mobile access point 137 is communicating with each ofthe first, second, and third mobile access points because the secondstationary access point 133 is between the first and third stationaryaccess points.

In some implementations, each stationary access point may also transmitinformation indicating the strength of a communication signal receivedfrom mobile access point 137 to the monitoring server 113. Themonitoring server 113 may use this communication signal strength toimprove the approximation of the location of mobile access point 137.The monitoring system may use known relationships between distance froma stationary access point and the strength of the communication signalto make these improved approximations. For example, the monitoringserver may approximate the location of the mobile access point 137 to becloser to a known location of the first stationary access point 131 thanto a known location of the second stationary access point 133 when themobile access point 137 is communicating with the first stationaryaccess point 131 with a stronger signal strength than with which it iscommunicating to the second stationary access point 133.

In some embodiments of the present invention, a content server 115 maydeliver information to at least one host device (e.g., 507) coupled tothe communication network based on the location of the mobile accesspoint 137, mobile host device 511, or vehicle 501 determined by themonitoring server 113. The information may be directed to the mobilehost device in the form of a web-based pop-up. The pop-up may, forexample, indicate to a user of the mobile host device 511 that thevehicle 501 is near a certain location (e.g., a train station). Thepop-up may be an advertisement for a business, museum, other touristattraction, or special event near a current location of the mobileaccess point 137 and the mobile host device 511. The information mayalso be in the form of an email.

In some embodiments, the vehicle 501 may travel among relatively fixedlocations at which passengers may load/unload the vehicle. For example,a train may travel among train stations, and a bus may travel among busstops. Network access may be facilitated at the fixed locations throughone or more antenna systems disposed at or near the fixed locations. Forexample, in some embodiments, one or more omnidirectional antennas whichare coupled to network 101 may be positioned at or near the fixedlocation to provide access to network 101 to mobile devices at or nearthe fixed location. In some embodiments, one or more lengths of leakycoaxial cable which are coupled to network 101 may be positioned at ornear the fixed location to provide access to network 101 to mobiledevices at or near the fixed location.

One or more of the fixed locations may include a large area. In suchsituations, multiple antennas or lengths of leaky coaxial cable may beused to provide access to network 101. The multiple antennas or lengthsof leaky coaxial may be positioned and arranged such that all orsubstantially all of the large area is provided with network access. Insome embodiments, for example, in which the fixed location includes alarge waiting room, as is typical in train stations, one or more lengthsof leaky coaxial cable may be positioned on opposing sides of the largewaiting room. The lengths of leaky coaxial cable may be configured toprovide network access through different wireless channels (e.g., 5channels of separation). By so positioning and arranging the lengths ofleaky coaxial cable, line of sight issues and interference problems maybe eliminated or minimized.

In some embodiments, one or more antenna systems (e.g., such as thoseillustrated in FIGS. 2, 3, or 4, leaky coaxial cable, etc.) may be partof or connect to an existing or future system. For example, in someembodiments, leaky coaxial cable that may, for example, be used within afixed location and/or a tunnel to provide network access, may be part ofan existing leaky coaxial system. The existing leaky coaxial system may,for example, include an emergency communication system or other existingcommunication system. The antennas may also connect to a system, such asa separate communication system, and thereby be shared among multiplesystems. For example, in one embodiment, the leaky coaxial may connectto a cellular system configured to provide cellular service withintunnels or at the fixed location or elsewhere.

Having described the structure of various components, operation of anexemplary embodiment of the present invention that is configured to usean ATM LANE is described below.

Referring to the flow charts of FIG. 8 and FIG. 9, which illustrateprocesses beginning at blocks 801 and 901 respectively, and the systemshown in FIG. 5 and FIG. 7, the mobile access point 137 may begin theprocess being coupled to the communication network 101 through the firststationary access point 131. The mobile access point may couple themobile devices 507, 511, 709, 711 to the communication network 101through the first stationary access point 131 as is indicated in block903 of the flow chart in FIG. 9.

A first host device 513 in the passenger car of FIG. 5, may attempt tocommunicate with the mobile access point 137 to authenticate and begincoupling to the communication network 101. When the host device 513attempts to communicate with the mobile access point 137, the mobileaccess point 137 may first authenticate the host device 513. Theauthentication process may require a user of the host device 513 toenter a login and password. The authentication process may also be basedon a physical address of the host device 513. To authenticate the hostdevice 513, the mobile access point 137 transmits a request to theauthentication server 105 through an ATM connection with the firststationary access point 131. The first stationary access point 131 mayinspect the physical layer destination of the authentication request andforward it on to the authentication server 105 through the communicationnetwork 101. The authentication server 105 may receive the request,perform a query on the authentication database and respond to therequest by transmitting an authentication response to the mobile accesspoint 137 though the communication network 101, and first stationaryaccess point 131 as ATM cells. When the mobile access point 137 receivesthe authentication response, if it includes a positive response, themobile access point 137 may couple the host device 513 to thecommunication network 101 through the first stationary access point 131.

The mobile access point 137, having communicated with the host device513 through one of its communication systems, now knows how tocommunicate with the host device 513 in the future (i.e., through thatsame communication system). The mobile access point 137 may store thisinformation in an address table so that the host device's physicaladdress is associated with the proper communication system. When datadirected to the host device 513 is received by the mobile access point137, the mobile access point 137 can determine which communicationsystem to forward the data through by referencing the address table. Themobile access point 137 may then transmit a topology change notification(TCN) to the first stationary access point 131. The TCN indicates thatthe host device 513 (identified by its physical address) can be accessedthough the mobile access point 137. The first stationary access point131 may record this information in its address table indicating that itcan communicate with the host device 513 through the communicationsystem used to communicate with the mobile access point 137 (e.g., anantenna system such as the second antenna system 205 of the firstexemplary stationary access point 201). The first stationary accesspoint 131 may then transmit a TCN through the communication network 101so other devices connected to the communication network 101 know how tocommunicate with the host device 513. Each device that receives the TCNmay establish an ATM virtual circuit to the host device or the mobileaccess point 137 to be used to communicate with the host device.

The mobile access point 137 may reach a location when it is within thecommunication range of the second stationary access point 133 asillustrated by block 905. Relatively soon after entering thecommunication range of the second stationary access point 133, themobile access point 137 may begin the process of transitioning tocoupling to the communication network 101 through the second stationaryaccess point 133 by authenticating itself with the second stationaryaccess point 133 as indicated in block 907 of FIG. 9. The secondstationary access point 133 may receive an authentication request fromthe mobile access point 137 as indicated in block 803 of FIG. 8. Thesecond stationary access point 133 may transmit an authenticationrequest to the authentication server 105 and/or an authentication cacheif the second stationary access point 133 is part of a stationary accesspoint group in order to authenticate the mobile access point 137 asindicated in block 805 of FIG. 8. The second stationary access point maytake different actions depending on whether the authentication wassuccessful, as indicated at block 807. If the second stationary accesspoint 133 receives a rejection from the authentication request it maydeny the mobile access point 137 access to the communication network asindicated in block 809 of FIG. 8. The process may then end at block 811.If the second stationary access point 133 receives a positiveauthentication response from the authentication server 105 orauthentication cache, the second stationary access point 133 may recordthe authentication information, as indicated in block 813 FIG. 8, andawait further communication from the mobile access point 137.

As the vehicle 501, and the mobile access point 137, move towards thesecond stationary access point 133 and away from the first stationaryaccess point 131, the communication signal from the second stationaryaccess point 133 may get stronger and the communication signal from thefirst stationary access point 131 may get weaker. The mobile accesspoint 137 may monitor the signal strength of the first and secondstationary access points as indicated in block 909 of FIG. 9.

At some point between the first and second stationary access points 131,133, the mobile access point 137 may request to couple to thecommunication network 101 through the second stationary access point 133instead of through the first stationary access point 131. As discussedabove, the mobile access point 137 may send this request approximatelywhen the strength of the communication signal from the second stationaryaccess point 133 exceeds the strength of the communication signal fromthe first stationary access point 131. The second stationary accesspoint 133 may receive this request, as indicated in block 815 of FIG. 8,and update its stored forwarding information and the forwardinginformation of other devices coupled to the communication network 101 asindicated in block 817 of FIG. 8, by, for example, establishing one ormore new ATM virtual circuits.

To update the forwarding information of other devices, the secondstationary access point 133 may transmit a TCN through the communicationnetwork 101. The TCN may indicate that the mobile access point 137 andany other devices coupled to the communication network 101 through themobile access point (including the host device 513) are accessiblethrough communication with the second stationary access point 133. Anydevices connected to the communication network 101 may receive the TCNand update their address tables to reflect this change. Any ATM devicesmay create new virtual circuits to the mobile device based on theupdated forwarding information.

After updating forwarding information, the second stationary accesspoint may couple the mobile access point 137 to the communicationnetwork 101, as indicated in block 819 of FIG. 8, by transferring databetween the mobile access point 137 and the communication network 101.When the signal strength of the second stationary access point 133exceeds some desired threshold or level as indicated at block 911, themobile access point 137 may then couple the mobile host devices 507,511, 709, 711 to the communication network 101 through the secondstationary access 133 point instead of the first stationary access point131 as indicated in block 913 of FIG. 9. By following this procedure,data may be forwarded to the mobile access point 137 and any devicescoupled to the communication network through the mobile access point 137as it moves from one stationary access point to the next. The process ofFIG. 9 may end at block 915.

If data is received by the communication network 101 (e.g., from theexternal network 125 or from a device coupled to the communicationnetwork 101) destined for the host device 513, the data may be forwardedthrough the communication network 101 through a plurality of forwardingdevices (e.g., 117, 119), as discussed above. The forwarding devices(117, 119) may examine their respective address tables to determine howto forward the data based on only data link layer information. Using theinformation in the forwarding tables, the data may be quickly forwardedto the host device 513 over long distances as if the host devices wereattached to a local network of the other devices coupled to thecommunication network 101.

The second stationary access point may continue to couple the mobileaccess point 137 to the communication network 101 until it receives aTCN indicating that the mobile access device has moved to a newstationary access point as indicated in block 821 of FIG. 8. The processmay then end at block 823.

If the mobile access point 137 is coupled to the communication network101 through the first stationary access point 131 when the data isreceived by the communication network 101 but the mobile access point137 moves to couple to the communication network 101 through the secondstationary access point 133 before the data reaches the mobile accesspoint 137 or the host device 513, the data may not be forwarded properlyto the host device 513. If the data does not reach the host device 513,data may be retransmitted to the communication network 101 in accordancewith a transport layer protocol (e.g., layer 4 of the OSI protocol),such as transmission control protocol (TCP), as is well-known in theart.

It should be recognized that the above described embodiments are givenas non-limiting examples only. Other embodiments may include anyarrangement and/or configuration desired. For example, in one embodimentof the present invention, the stationary access points may themselves bearranged on a moving platform such as a train or other vehicle. Thestationary access points may be configured to communicate with a mobiledevice that is relatively stationary compared to the moving stationaryaccess points. The stationary access points may be arranged such thatthe mobile device is in communication with at least one stationaryaccess point as the platform or vehicle passes near the mobile device.

Having thus described several aspects of at least one embodiment of thisinvention, it is to be appreciated various alterations, modifications,and improvements will readily occur to those skilled in the art. Suchalterations, modifications, and improvements are intended to be part ofthis invention, and are intended to be within the scope of theinvention. Accordingly, the foregoing description and drawings are byway of example only.

1. A communication system comprising: a first antenna system comprising a plurality of first antennas mounted to a first supporting structure, each of the plurality of first antennas having a main lobe oriented in a different direction; and a second antenna system comprising a plurality of second antennas mounted to a second supporting structure, each of the plurality of second antennas having a main lobe oriented in a different direction, the main lobe of at least one of the plurality of second antennas being oriented in a direction opposing the main lobe of at least one of the plurality of first antennas, wherein the first antenna system and the second antenna system are disposed at spaced apart positions along or adjacent to a path traversed by a vehicle, such that the vehicle does not substantially obstruct the main lobes of the plurality of first antennas or the plurality of second antennas as the vehicle traverses the path.
 2. The communication system of claim 1, wherein at least 40% of an energy radiated from a first antenna of the plurality of first antennas and from a second antenna of the plurality of second antennas is not obstructed by the vehicle as the vehicle traverses the path.
 3. The communication system of claim 1, wherein the first antenna system includes at least one of a battery and a solar power supply configured to power the plurality of first antennas.
 4. The communication system of claim 1, further comprising a mobile antenna coupled to the vehicle; wherein the first antenna system is configured to communicate with the mobile antenna through at least one of the plurality first antennas when the mobile antenna is with a communication range of the first antenna system, and the second antenna system is configured to communicate with the mobile antenna through at least one of the plurality of second antennas when the mobile antenna is within a communication range of the second antenna system.
 5. The communication system of claim 4, wherein the communication range of the first antenna system overlaps the communication range of the second antenna system.
 6. The communication system of claim 4, wherein each of the first and second antenna systems is coupled to a communication network.
 7. The communication system of claim 6, wherein the first antenna system is coupled to the communication network through a wired connection.
 8. The communication system of claim 7, wherein the second antenna system is coupled to the communication network through the first antenna system.
 9. The communication system of claim 8, wherein the second antenna system is coupled to the communication network through the first antenna system by a wired connection to the first antenna system.
 10. The communication system of claim 8, wherein the second antenna system is coupled to the communication network through the first antenna system by a wireless network with the first antenna system.
 11. The communication system of claim 10, wherein the first antenna system includes at least one third antenna communicating over the wireless network to at least one fourth antenna of the second antenna system to couple the second antenna system to the communication network through the first antenna system.
 12. The communication system of claim 10, wherein the wireless network includes a wireless network using an IEEE 802.11 protocol.
 13. The communication system of claim 6, wherein the mobile antenna is coupled to a mobile access point configured to provide a plurality of host devices access to the communication network through communication with the first and second antenna systems.
 14. The communication system of claim 13, wherein the plurality of host devices includes at least one of a laptop computer, a personal digital assistant (PDA), and a cellular telephone.
 15. The communication system of claim 13, wherein the mobile access point is configured to provide access to the communication network through the first antenna system when a first signal strength of the first antenna system is stronger than a second signal strength of the second antenna system.
 16. The communication system of claim 15, wherein the mobile access point is configured to provide access to the communication network through the second antenna system when the second signal strength is stronger than the first signal strength.
 17. The communication system of claim 16, wherein the mobile access point is configured to authenticate with the second antenna system before the second signal strength is stronger than the first signal strength.
 18. The communication system of claim 17, wherein the mobile access point communicates with the first and second antenna systems through a wireless network.
 19. The communication system of claim 18, wherein the wireless network includes a wireless network using an IEEE 802.11 protocol.
 20. The communication system of claim 13, wherein the mobile access point communicates with the plurality of host devices through at least one wireless network.
 21. The communication system of claim 20, wherein the at least one wireless network includes a wireless network using an IEEE 802.11 protocol.
 22. An antenna system for communicating with a mobile device, comprising: a support; a plurality of first antennas mounted to the support, each first antenna of the plurality of first antennas being configured to communicate with the mobile device when the mobile device is more than a minimum communication distance from the support and less than a maximum communication distance from the support; and at least one second antenna mounted to the support and configured to communicate with the mobile device when the mobile device is less than the minimum communication distance from the support.
 23. The communication system of claim 22, wherein the communication system further comprises at least one connection device coupled to the support and configured to communicate with a communication network.
 24. The communication system of claim 23, wherein the mobile device includes a mobile access point and the communication system is configured to provide access to the communication network to a plurality of host devices coupled to the mobile access point by communicating with the mobile access point through at least one of the plurality of first antennas and the at least one second antenna.
 25. The communication system of claim 23, wherein the at least one connection device comprises a plurality of third antennas mounted to the support.
 26. The communication system of claim 25, wherein at least one antenna of the plurality of third antennas is configured to communicate with at least one second communication system.
 27. The communication system of claim 26, wherein the at least one antenna of the plurality of third antennas is configured to communicate with the communication network through a wireless network with the at least one second communication system.
 28. The communication system of claim 27, wherein the wireless network includes a wireless network using an IEEE 802.11 communication protocol.
 29. The communication system of claim 23, wherein the at least one connection device comprises a wired connection to the communication network.
 30. The communication system of claim 29, wherein the wired connection includes at least one of a wire and an optical fiber.
 31. The communication system of claim 29, wherein the wired connection connects the communication system to a forwarding device coupled to the communication network.
 32. The communication system of claim 29, wherein the wired connection to the communication network includes at least one wired connection to at least one second communication system.
 33. The communication system of claim 22, wherein the plurality of first antennas are parabolic dish antennas and the at least one second antenna is an omnidirectional antenna. 